The Gadsden Purchase (known as Venta de La Mesilla, or Sale of La Mesilla, in Mexico) is a 29,670-square-mile (76,800 km2) region of present-day southern Arizona and southwestern New Mexico that was purchased by the United States in a treaty signed by James Gadsden, the American ambassador to Mexico at the time, on December 30, 1853. It was then ratified, with changes, by the U.S. Senate on April 25, 1854 and signed by President Franklin Pierce, with final approval action taken by Mexico on June 8, 1854. The purchase was the last major territorial acquisition in the contiguous United States, adding a large area to the United States.
The purchase included lands south of the Gila River and west of the Rio Grande; it was largely for the purpose that the US might construct a transcontinental railroad along a deep southern route. It also aimed to reconcile outstanding border issues between the US and Mexico following the Treaty of Guadalupe Hidalgo, which ended the Mexican–American War of 1846–48.
As the railroad age progressed, business-oriented Southerners saw that a railroad linking the South with the Pacific Coast would expand trade opportunities. They thought the topography of the southern portion of the Mexican Cession was too mountainous to allow a direct route. Projected southern routes tended to run to the north at their eastern ends, which would favor connections with northern railroads and ultimately favor northern seaports. Southerners saw that to avoid the mountains, a route with a southeastern terminus might need to swing south into what was then Mexican territory.
The administration of President Franklin Pierce, strongly influenced by Secretary of War Jefferson Davis, saw an opportunity to acquire land for the railroad, as well as to acquire significant other territory from northern Mexico. In the end, territory for the railroad was purchased for $10 million ($260 million today), but Mexico balked at any large-scale sale of territory. In the United States, the debate over the treaty became involved in the sectional dispute over slavery, ending progress before the American Civil War in the planning or construction of a transcontinental railroad.
Southern route for the Transcontinental Railroad 
Southern commercial conventions 
In January 1845 Asa Whitney of New York state presented the US Congress with the first plan to construct a transcontinental railroad. Although Congress took no action on his proposal, a commercial convention of 1845 in Memphis took up the issue. Prominent attendees included John C. Calhoun, Clement C. Clay, Sr., John Bell, William Gwin, and Edmund P. Gaines, but it was James Gadsden of South Carolina who was influential in the convention’s recommending a southern route for the proposed railroad, beginning in Texas and ending in San Diego or Mazatlán. Southerners hoped that such a route would ensure southern prosperity while opening the “West to southern influence and settlement.”
Southern interest in railroads in general, and the Pacific railroad in particular, accelerated after the conclusion of the Mexican-American War in 1848. During that war, topographical officers William H. Emory and James W. Abert had conducted surveys that demonstrated the feasibility of a railroad's originating in El Paso or western Arkansas and ending in San Diego. J. D. B. DeBow, the editor of DeBow's Review, and Gadsden both publicized within the South the benefits of building this railroad.
Gadsden had become the president of the South Carolina Canal and Rail Road Company in 1839; about a decade later, the company had laid 136 miles (219 km) of track extending west from Charleston, South Carolina, and it was 3 million dollars in debt. Gadsden wanted to connect all Southern railroads into one sectional network. He was concerned that the increasing railroad construction in the North was shifting trade in lumber, farm goods, and manufacturing goods from the traditional north-south route based on the Ohio and Mississippi rivers to an east-west axis that would bypass the South. He also saw Charleston, his home town, losing its prominence as a seaport. In addition, many Southern business interests feared that a northern transcontinental route would cut the South off from trade with the Orient. Other Southerners argued for diversification from a plantation economy to keep the South independent from northern bankers.
In October 1849 a convention to discuss railroads was held in Memphis, in response to a separate convention called in St. Louis earlier in the fall, which had discussed a northern route. The Memphis convention overwhelmingly advocated the construction of a route beginning there, to connect with an El Paso to San Diego line. Disagreement arose only over the issue of financing. The convention president, Matthew Fontaine Maury of Virginia, preferred strict private financing, whereas John Bell and others thought that Federal land grants to railroad developers would be necessary.
James Gadsden and California 
Gadsden had supported nullification in 1831. In 1850 he advocated secession by South Carolina when California was admitted to the Union as a free state. Gadsden considered slavery “a social blessing” and abolitionists “the greatest curse of the nation”.
When the secession proposal failed, Gadsden, working with his cousin Isaac Edward Holmes, a lawyer in San Francisco since 1851, and the California state senator Thomas Jefferson Green, attempted to divide California in two. They proposed that the southern half would allow slavery. Gadsden planned to establish a slaveholding colony there based on rice, cotton, and sugar. He would use slave labor to build a railroad and highway, originating in either San Antonio or on the Red River, that would transport people to the California gold fields. Toward this end, on December 31, 1851, Gadsden asked Green to secure from the California state legislature a large land grant located between the 34th and 36th parallels; it would eventually serve as the dividing line for the two California states.
A few months after this, Gadsden and 1,200 potential settlers from South Carolina and Florida submitted a petition to the California legislature for permanent citizenship and permission to establish a rural district that would be farmed by "not less than Two Thousand of their African Domestics". The petition stimulated some debate, but it finally died in committee.
Stephen Douglas and land grants 
The Compromise of 1850, which created the Utah Territory and the New Mexico Territory, would facilitate a southern route to the West Coast since all territory for the railroad was now organized and would allow for Federal land grants as a financing measure. Competing northern or central routes championed, respectively, by Stephen Douglas of Illinois and Thomas Hart Benton of Missouri would still need to go through unorganized territories. A precedent for using federal land grants had been established when Millard Fillmore signed a bill promoted by Douglas that allowed a Mobile to Chicago railroad to be financed by "federal land grants for the specific purpose of railroad construction". To satisfy Southern opposition to the general principle of Federally supported internal improvements, the land grants would first be transferred to the appropriate state or territorial government, which would oversee the final transfer to private developers.
By 1850, however, the majority of the South was not interested in exploiting its advantages in developing a transcontinental railroad or railroads in general. Businessmen like Gadsden, who advocated economic diversification, were in the minority. The Southern economy was based on cotton exports, and then-current transportation networks met the plantation system's needs. There was little home market for an intra-South trade. In the short term, the best use for capital was to invest it in more slaves and land rather than in taxing it to support canals, railroads, roads, or in dredging rivers. Historian Jere W. Roberson wrote:
Southerners might have gained a great deal under the 1850 land grant act had they concentrated their efforts. But continued opposition to Federal aid, filibustering, an unenthusiastic President, the spirit of "Young America", and efforts to build railroads and canals across Central America and the Isthmus of Tehuantepec in Mexico divided their forces, leaving a lot of time for the Pacific railroad. Moreover, the Compromise of 1850 encouraged Southerners not to antagonize opponents by resurrecting the railroad controversy.—Jere W. Roberson, The South and the Pacific Railroad, 1845-1855
Treaty of Guadalupe-Hidalgo 
The Treaty of Guadalupe Hidalgo ended the Mexican-American War, but there were issues affecting both sides that still needed to be resolved: possession of the Mesilla Valley, protection for Mexico from Indian raids, and the right of transit in the Isthmus of Tehuantepec.
Mesilla Valley 
The treaty provided for a joint commission, made up of a surveyor and commissioner from each country, to determine the final boundary between the United States and Mexico. The treaty specified that the Rio Grande Boundary would veer west eight miles (13 km) north of El Paso. The treaty was based on the attached 1847 copy of a twenty-five-year-old map. Surveys revealed that El Paso was 36 miles (58 km) further south and 100 miles (160 km) further west than the map showed. Mexico favored the map, but the United States put faith in the results of the survey. The disputed territory involved a few thousand square miles and about 3,000 residents; more significantly, it included the Mesilla Valley. Bordering the Rio Grande, the valley consisted of flat desert land measuring about 50 miles (80 km), north to south, by 200 miles (320 km), east to west. This valley was essential for the construction of a transcontinental railroad using a southern route.
John Bartlett of Rhode Island, the United States negotiator, agreed to allow Mexico to retain the Mesilla Valley (setting the boundary at 32° 22′ N, north of the American claim 31° 52′ and at the easternmost part, also north of the Mexican-claimed boundary at 32° 15′) in exchange for a boundary not turning north until 110° W in order to include the Santa Rita Mountains, which were believed to have rich copper deposits, and some silver and gold which had not yet been mined. Southerners opposed this alternative because of its implication for the railroad, but it was supported by President Fillmore. Southerners in Congress prevented any action on the approval of this separate border treaty and eliminated further funding for surveying of the disputed borderland. Bartlett was replaced with Robert Blair Campbell, a pro-railroad politician from Alabama. Mexico asserted that the commissioners' determinations were valid and prepared to send in troops to enforce the unratified agreement.
Indian raids 
Article XI of the Treaty of Guadalupe-Hidalgo contained a guarantee that the United States would protect Mexicans by preventing cross-border raids by Native American tribes. At the time the treaty was ratified, Secretary of State James Buchanan had believed that the United States had both the commitment and resources to enforce this promise. Historian Richard Kluger, however, described the difficulties of the task:
|“||Commanche, Apache, and other tribal warriors had been punishing Spanish, Mexican, and American intruders into their stark homeland for three centuries and been given no incentive to let up their murderous marauding and pillaging, horse stealing in particular. The U. S. Army had posted nearly 8,000 of its total of 11,000 soldiers along the southwestern boundary, but they could not halt the 75,000 or so native nomads in the region from attacking swiftly and taking refuge among the hills, buttes, and arroyos in a landscape where one’s enemies could be spotted twenty or thirty miles away.||”|
In the five years after approval of the Treaty, the United States spent $12 million ($310,000,000 today) in this area, and General Winfield Scott estimated that five times that amount would be necessary to police the border. Mexican officials, frustrated with the failure of the United States to effectively enforce its guarantee, demanded reparations for the losses inflicted on Mexican citizens by the raids. The United States argued that the Treaty did not require any compensation nor did it require any greater effort to protect Mexicans than was expended in protecting its own citizens. During the Fillmore administration, Mexico claimed damages of $40 million ($1,000,000,000 today) but offered to allow the U. S. to buy out Article XI for $12 million ($640,000,000 today). Fillmore had proposed a settlement that was $10 million less.
Isthmus of Tehuantepec 
During negotiations of the treaty, Americans had failed to secure the right of transit across the 125-mile (201 km)-wide Isthmus of Tehuantepec. The idea of building a railroad here had been considered for a long time. In 1842 Mexican President Antonio López de Santa Anna sold the rights to build a railroad or canal across the isthmus. The deal included land grants 300 miles (480 km)-wide along the right-of-way for future colonization and development. In 1847 a British bank bought the rights, raising US fears of British colonization in the hemisphere, in violation of the precepts of the Monroe Doctrine. United States interest in the right-of-way was increased by the 1848 discovery of gold in California.
The Memphis commercial convention of 1849 recommended that the United States pursue the trans-isthmus route, since it appeared unlikely that a transcontinental railroad would be built anytime soon. Interests in Louisiana were especially adamant about this option, as they believed that any transcontinental railroad would divert commercial traffic away from the Mississippi and New Orleans, and they at least wanted to secure a southern route. Also showing interest was Peter A. Hargous of New York who ran an import-export business between New York and Vera Cruz. Hargous purchased the rights to the route for $25,000 ($700,000 today), but realized that the grant had little value unless it was supported by the Mexican and American governments.
In Mexico, topographical officer George W. Hughes reported to Secretary of State John M. Clayton that a railroad across the isthmus was a “feasible and practical” idea. Clayton then instructed Robert P. Letcher, the minister to Mexico, to negotiate a treaty to protect Hargous’ rights. The United States’ proposal gave Mexicans a 20% discount on shipping, guaranteed Mexican rights in the zone, allowed the United States to send in military if necessary, and gave the United States most-favored-nation status for Mexican cargo fees. This treaty, however, was never finalized.
The Clayton-Bulwer Treaty between the United States and Great Britain, which guaranteed the neutrality of any such canal, was finalized in April 1850. Mexican negotiators refused the treaty because it would eliminate Mexico's ability to play the U.S. and U.K. against each other. They eliminated the right of the United States to unilaterally intervene militarily. The United States Senate approved the treaty in early 1851, but the Mexican Congress refused to accept the treaty.
In the meantime, Hargous proceeded as if the treaty would be approved eventually. Judah P. Benjamin and a committee of New Orleans businessmen joined with Hargous and secured a charter from the Louisiana legislature to create the Tehuantepec Railroad Company. The new company sold stock and sent survey teams to Mexico. Hargous started to acquire land even after the Mexican legislature rejected the treaty, a move that led to the Mexicans canceling Hargous’ contract to use the right of way. Hargous put his losses at $5 million ($138,000,000 today) and asked the United States government to intervene. President Fillmore refused to do so.
Mexico sold the canal franchise, without the land grants, to A. G. Sloo and Associates in New York for $600,000 ($17,000,000 today). In March 1853 Sloo contracted with a British company to build a railroad and sought an exclusive contract from the new Franklin Pierce Administration to deliver mail from New York to San Francisco. However, Sloo soon defaulted on bank loans and the contract was sold back to Hargous.
Pierce administration 
The Pierce administration, which took office in March 1853, had a strong pro-southern, pro-expansion mindset. Louisiana Senator Pierre Soulé was sent to Spain to negotiate the annexation of Cuba. Expansionists John Y. Mason of Virginia and Solon Borland of Arkansas were appointed as ministers, respectively, to France and Nicaragua. Pierce's Secretary of War, Jefferson Davis, was already on record as favoring a southern route for a transcontinental railroad, so southern rail enthusiasts had every reason to be encouraged.
The South as a whole, however, remained divided. In January 1853 Senator Thomas Jefferson Rusk of Texas introduced a bill to create two railroads, one with a northern route and one with a southern route starting below Memphis on the Mississippi River. Under the Rusk legislation, the President would be authorized to select the specific termini and routes as well as the contractors who would build the railroads. Some southerners, however, worried that northern and central interests would leap ahead in construction and opposed any direct aid to private developers on constitutional grounds. Other southerners preferred the isthmian proposals. An amendment was added to the Rusk bill to prohibit direct aid, but southerners still split their vote in Congress and the amendment failed.
This rejection led to legislative demands, sponsored by William Gwin of California and Salmon P. Chase of Ohio and supported by the railroad interests, for new surveys for possible routes. Gwin expected that a southern route would be approved — both Davis and Robert J. Walker, former secretary of the treasury, supported it. Both were stockholders in a Vicksburg-based railroad that planned to build a link to Texas to join up with the southern route. Davis argued that the southern route would have an important military application in the likely event of future troubles with Mexico.
Gadsden and Santa Anna 
On March 21, 1853, a treaty initiated in the Fillmore administration, that would provide joint Mexican and United States protection for the Sloo grant was signed in Mexico. At the same time that this treaty was received in Washington, Pierce learned that New Mexico Territorial Governor William C. Lane had issued a proclamation claiming the Mesilla Valley as part of New Mexico, leading to protests from Mexico. Pierce was also aware of efforts by France, through its consul in San Francisco, to acquire the Mexican state of Sonora.
Pierce recalled Lane in May and replaced him with David Meriwether of Kentucky. Meriwether was given orders to stay out of the Mesilla Valley until negotiations with Mexico could be completed. With the encouragement of Davis, Pierce also appointed James Gadsden to negotiate with Mexico over the acquisition of additional territory. Secretary of State William L. Marcy gave Gadsden clear instructions: he was to secure the Mesilla Valley for the purposes of building a railroad through it, convince Mexico that the US had done its best regarding the Indian raids, and elicit Mexican cooperation in efforts by US citizens to build a canal or railroad across the Tenhuantepec isthmus. Supporting the Sloo interests was not part of the instructions.
The Mexican government was going through political and financial turmoil. In the process, Santa Anna had been returned to power about the same time that Pierce was inaugurated. Santa Anna was willing to deal because he needed money to rebuild the Mexican Army for defense against the United States, but he initially rejected the extension of the border further south to the Sierra Madre Mountains. He initially insisted on reparations for the damages caused by American Indian raids, but agreed to let an international tribunal resolve this. Gadsden realized that Santa Anna needed money and passed this information along to Secretary Marcy.
Marcy and Pierce responded with new instructions. Gadsden was authorized to purchase any of six parcels of land with a price fixed for each. The price would include the settlement of all Indian damages and relieve the United States from any further obligation to protect Mexicans. $50 million ($1.4 billion today) would have bought the Baja California Peninsula and a large portion of its northwestern Mexican states while $15 million ($410,000,000 today) was to buy the 38,000 square miles (98,000 km2) of desert necessary for the railroad plans.
Santa Anna was put off by "Gadsden’s antagonistic manner". Gadsden had advised Santa Anna that "the spirit of the age" would soon lead the northern states to secede so he might as well sell them now. The Mexican President felt threatened by William Walker's attempt to capture Baja California with 50 troops and annex Sonora. Gadsden disavowed any government backing of Walker, who was expelled by the US and placed on trial as a criminal. Santa Anna worried that the US would allow further aggression against Mexican territory. Santa Anna needed to get as much money for as little territory as possible. When Great Britain rejected Mexican requests to assist in the negotiations, Santa Anna opted for the $15 million package.
Pierce and his cabinet began debating the treaty in January 1854. Although disappointed in the amount of territory secured and some of the terms, they submitted it to the Senate on February 10. Gadsden, however, suggested that northern senators would block the treaty in order to deny the South a railroad.
Although signed by Pierce and Santa Anna, the treaty needed to be ratified by a 2/3 vote of the U.S. Senate, where it met strong opposition. Antislavery senators opposed further acquisition of slave territory. Lobbying by speculators gave the treaty a bad reputation. Some senators objected to furnishing Santa Anna financial assistance.
The treaty had reached the Senate as that body was focused on the debate over the Kansas-Nebraska Act. On April 17, after much debate, the Senate voted 27 to 18 in favor of the treaty, falling three votes short of the necessary two-thirds required for treaty approval. After this defeat, Secretary Davis and southern senators pressed Pierce to add more provisions to the treaty including:
- protection for the Sloo grant;
- a requirement that Mexico “protect with its whole power the prosecution, preservation, and security of the work [referring to the isthmian canal]”;
- permission for the United States to intervene unilaterally “when it may feel sanctioned and warranted by the public or international law”; and
- a reduction of the territory to be acquired by 9,000 square miles (23,000 km2) and dropping the price from $15 million ($383,277,778) to $10 million ($255,518,519).
This version of the treaty successfully passed the U.S. Senate April 25, 1854 by a vote of 33 to 12. The reduction in territory was an accommodation of northern senators who opposed the acquisition of additional slave territory. In the final vote, northerners split 12 to 12. Gadsden took the revised treaty back to Santa Anna, who accepted the changes. The treaty went into effect June 30, 1854.
While the land was available for construction of a southern railroad, the issue had become too strongly associated with the sectional debate over slavery to receive federal funding. Roberson wrote:
The unfortunate debates in 1854 left an indelible mark on the course of national politics and the Pacific railroad for the remainder of the antebellum period. It was becoming increasingly difficult, if not outright impossible, to consider any proposal that could not somehow be construed as relating to slavery and, therefore, sectional issues. Although few people fully realized it at the close of 1854, sectionalism had taken such a firm, unrelenting hold on the nation that completion of an antebellum Pacific railroad was prohibited. Money, interest, and enthusiasm were devoted to emotion-filled topics, not the Pacific railroad.—Jere W. Roberson, The South and the Pacific Railroad, 1845-1855
The effect was such that railroad development, which accelerated in the North, stagnated in the South.
Post-ratification controversy 
As originally envisioned, the purchase would have encompassed a much larger region, extending far enough south to include most of the current Mexican states of Baja California, Baja California Sur, Coahuila, Chihuahua, Sonora, Nuevo León, and Tamaulipas. The Mexican people opposed such boundaries, as did anti-slavery U.S. Senators, who saw the purchase as acquisition of more slave territory. Even the sale of a relatively small strip of land angered the Mexican people, who saw Santa Anna's actions as a betrayal of their country. They watched in dismay as he squandered the funds generated by the Purchase. Contemporary Mexican historians continue to view the deal negatively and believe that it has defined the American-Mexican relationship in a deleterious way.
The purchased lands were initially appended to the existing New Mexico Territory. To help control the new land, the U.S. Army established Fort Buchanan on Sonoita Creek in present-day southern Arizona on November 17, 1856. The difficulty of governing the new areas from the territorial capital at Santa Fe, NM led to efforts as early as 1856 to organize a new territory out of the southern portion. Many of the early settlers in the region were, however, pro-slavery and sympathetic to the South, resulting in an impasse in Congress as to how best to reorganize the territory.
The shifting of the course of the Rio Grande would cause a later dispute over the boundary between Purchase lands and those of the state of Texas, known as the Country Club Dispute. Pursuant to the Treaty of Guadalupe Hidalgo, the Gadsden Treaty and subsequent treaties, the International Boundary and Water Commission which was established in 1889 to maintain the border, and pursuant to still later treaties its duties expanded to allocation of river waters between the two nations, and providing for flood control and water sanitation. Once viewed as a model of international cooperation, in recent decades the IBWC has been heavily criticized as an institutional anachronism, by-passed by modern social, environmental and political issues.
Growth of the region after 1854 
Army control 
The residents of the area gained full U.S. citizenship and slowly assimilated into American life over the next half-century. The principal threat to the peace and security of settlers and travelers in the area were raids by Apache Indians. The U.S. Army took control of the purchase lands in 1854 but not until 1856 were troops stationed in the troubled region. In June 1857 it established Fort Buchanan south of the Gila at the head of the Sonoita Creek Valley. The fort protected the area until it was evacuated and destroyed in July 1861. The new stability brought miners and ranchers. By the late 1850s, mining camps and military posts had not only transformed the Arizona countryside; they had also generated new trade linkages to the province of Sonora, Mexico. Magdalena, Sonora, became a supply center for Tubac, wheat from nearby Cucurpe fed the troops at Fort Buchanan, and the town of Santa Cruz sustained the Mowry mines, just miles to the north.
Civil War 
In 1861, during the American Civil War, the Confederate States of America formed the Confederate Territory of Arizona, including in the new territory mainly areas acquired by the Gadsden Purchase. In 1863, using a north-to-south dividing line, the Union created its own Arizona Territory out of the western half of the New Mexico Territory. The new American Arizona Territory also included most of the lands acquired in the Gadsden Purchase. This territory would be admitted into the Union as the State of Arizona on February 14, 1912, the last area of the Lower 48 States to receive statehood.
Social development 
After the Gadsden Purchase, southern Arizona's social elite, including the Estevan Ochoa, Mariano Samaniego, and Leopoldo Carillo families, remained primarily Mexican American until the coming of the railroad in the 1880s. When the Sonora Exploring and Mining Company opened silver mines in southern Arizona, it sought to employ educated, middle-class Americans who shared a work ethic and leadership abilities to operate the mines. A biographical analysis of some 200 of its employees, classed as capitalists, managers, laborers, and general service personnel, reveals that the resulting work force included Europeans, Americans, Mexicans, and Indians. This mixture failed to stabilize the remote area, which lacked formal social, political, and economic organization in the years from the Gadsden Purchase to the Civil War. From the late 1840s into the 1870s Texas stockmen drove their beef cattle over southern Arizona on the Texas-California trail. Texans were impressed with the grazing possibilities offered by the Gadsden Purchase country of Arizona. By the last third of the century they were moving their herds into Arizona and establishing the range cattle industry there. Not only did the Texans contribute their proven range methods to the new grass country of Arizona but their problems as well. Texas rustlers brought lawlessness, poor management resulted in overstocking, and carelessness introduced destructive diseases. But these difficulties did force laws and associations in Arizona to curb and resolve them. The Anglo-American cattleman frontier in Arizona was an extension of the Texas experience.
Railroad development 
The Southern Pacific Railroad from Los Angeles reached Yuma, Arizona, in 1877, Tucson in March 1880, El Paso in May 1881, and this completed the second transcontinental railroad in December 1881. The portion in Arizona was originally largely in the Gadsden Purchase but the western part was later rerouted north of the Gila River to serve the city of Phoenix. The portion in New Mexico runs largely through the territory that had been disputed between Mexico and the United States after the Treaty of Guadalupe Hidalgo had gone into effect, and before the time of the Gadsden Purchase. The Santa Fe Railroad Company also completed a railroad across Northern Arizona, via Prescott, Winslow, Flagstaff, and Kingman in August 1883.
The remainder of the Gila Valley pre-Purchase border area was traversed by the Arizona Eastern Railway by 1899 and the Copper Basin Railway by 1904. Excluded was a 20-mile (32 km) section in the San Carlos Apache Indian Reservation, from today's San Carlos Lake to Winkelman at the mouth of the San Pedro River, including the Needle's Eye Wilderness.
The section of U.S. Highway 60 about 20 miles (32 km) to the northwest, between Superior and Miami via Top-of-the-World, takes an alternate route (17.4 road miles) between the Magma Arizona Railroad and the Arizona Eastern Railway railheads on each side of this gap. This highway is well north of the Gadsden Purchase. Given the elevations of those three places, at least a 3% grade would have been required.
The suburb Sunland Park (pop. 13,309 in 2000), of El Paso, Texas in Doña Ana County, New Mexico, is the largest community of New Mexico in the Gadsden Purchase. Lordsburg, New Mexico (pop. 3,379 in 2000), the county seat of Hidalgo County, was in the disputed area before the Gadsden Purchase, and Deming, New Mexico, the county seat of Luna County, was north of both the Mexican and American land claims before the Gadsden Purchase, though the proposed Bartlett-Conde compromise of 1851 would have left it in Mexico.
The boundaries of most counties in Arizona do not follow the northern boundary of the Gadsden Purchase, but six counties in Arizona do have most of their populations within the land of the Gadsden Purchase. Four of these also contain areas north of the Gadsden Purchase, but these areas do have low population densities, with the exception of northeastern Pinal County, AZ, including the towns of Apache Junction and Florence. Maricopa County also extends south into the area of the Gadsden Purchase, but this area is also thinly populated.
The northmost point of the Gadsden Purchase, and also along the American-Mexican border during period of 1848 - 53 is at approximately Goodyear, Arizona, about 30 miles (48 km) southwest of Phoenix.in the town of
See also 
- Butterfield Overland Mail
- Historic regions of the United States
- Mexico – United States border
- Republic of Sonora
- William L. Marcy. "The Avalon Project: Gadsden Purchase Treaty: December 30, 1853". Yale University. Retrieved 2008-10-10. The Purchase treaty defines the new border as "up the middle of that river (the Rio Grande) to the point where the parallel of 31° 47' north latitude crosses the same ; thence due west one hundred miles; thence south to the parallel of 31° 20' north latitude; thence along the said parallel of 31° 20' to the 111th meridian of longitude west of Greenwich ; thence in a straight line to a point on the Colorado River twenty English miles below the junction of the Gila and Colorado rivers; thence up the middle of the said river Colorado until it intersects the present line between the United States and Mexico." The new border included a few miles of the Colorado River at the western end; the remaining land portion consisted of line segments between points, including at the Colorado River, west of Nogales at , near AZ-NM-Mexico tripoint at , the eastern corners of NM southern bootheel (Hidalgo County) at , and the west bank of Rio Grande at
- Ibarra, Ignacio (2004-02-12). "Land sale still thorn to Mexico: Historians say United States imperialism behind treaty". Arizona Daily Star. Archived from the original on May 3, 2007. Retrieved 2007-10-04.
- Nevins p. 84.
- Roberson pp. 163-164.
- Roberson p. 165.
- Richards p. 125.
- Kluger p. 485.
- Roberson p. 166.
- Richards p. 126.
- Richards p. 127.
- Kluger p. 487. Roberson p. 169.
- Roberson p. 168.
- Kluger p. 487.
- Kluger p. 488.
- Roberson p. 169.
- Kluger p. 491.
- The Treaty of Guadalupe Hidalgo: A Legacy of Conflict By Richard Griswold del Castillo, page 57. Books.google.com. Retrieved 2011-05-28.
- Kluger pp. 491-492. Roberson p. 171.
- Kluger p. 492.
- Roberson p. 182. Kluger p. 493.
- Kluger pp. 493-494. Roberson p. 182.
- Kluger p. 494.
- Roberson p. 182.
- Kluger pp. 494-495.
- Nevins p. 48.
- Roberson p. 170.
- Jeffrey Gordon Mauck, "The Gadsden Treaty: The Diplomacy of Transcontinental Transportation." PhD dissertation Indiana U. 1991. 278 pp. DAI 1992 52(9): 3405-A. DA9205951 Fulltext: ProQuest Dissertations & Theses
- Roberson pp. 170-171.
- Roberson p. 172. Kluger p. 490.
- Nichols p. 265.
- Nichols p. 266. Kluger p. 496. Roberson p. 183.
- Kluger pp. 497-498.
- Kluger pp. 498-499.
- Nichols p. 325.
- "Article 3 -- No Title". The New York Times. April 25, 1854.
- Kluger pp. 502-503. David N. Potter, The Impending Crisis 1848-1861 (1976) p. 183.
- Paul Neff Garber, The Gadsden Treaty (1923)
- Roberson p. 180.
- Kluger p. 504.
- Robert J. McCarthy, Executive Authority, Adaptive Treaty Interpretation, and the International Boundary and Water Commission, U.S.-Mexico, 14-2 U. Denv. Water L. Rev. 197(Spring 2011) (also available for free download at http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1839903).
- Marcy Gail Goldstein, "Americanization and Mexicanization: The Mexican Elite and Anglo-Americans in the Gadsden Purchase Lands, 1853-1880". PhD dissertation Case Western Reserve U. 1977. 342 pp. DAI 1977 38(3): 1572-1573-A.
- Ben Sacks, "The Origins of Fort Buchanan: Myth and Fact". Arizona and the West 1965 7(3): 207-226. Issn: 0004-1408
- Thomas E. Sheridan, "Peacock in the Parlor: Frontier Tucson's Mexican Elite". Journal of Arizona History 1984 25(3): 245-264. Issn: 0021-9053
- Diane North, "'A Real Class of People' in Arizona: a Biographical Analysis of the Sonora Exploring and Mining Company, 1856-1863". Arizona and the West 1984 26(3): 261-274. Issn: 0004-1408
- James A. Wilson, "West Texas Influence on the Early Cattle Industry of Arizona". Southwestern Historical Quarterly 1967 71(1): 26-36. Issn: 0038-478x
- David Devine, Slavery, Scandal, and Steel Rails: The 1854 Gadsden Purchase and the Building of the Second Transcontinental Railroad Across Arizona and New Mexico Twenty-Five Years Later (2004)
- "Second Transcontinental Line brings competition". Railswest.com. Retrieved 2011-05-28.
- Arizona Railroad Map. Retrieved August 1, 2008.
- Arizona Eastern Railway Map. Retrieved August 1, 2008.
- Garber, Paul Neff. The Gadsden Treaty (1923) 222 pp; the standard diplomatic history
- Kluger, Richard. Seizing Destiny: How America Grew From Sea to Shining Sea. (2007) ISBN 978-0-375-41341-4.
- Nevins, Allan. Ordeal of the Union: A House Dividing 1852-1857. (1947) SBN 684-10424-5.
- Nichols, Roy Franklin. Franklin Pierce: Young Hickory of the Granite Hills. (1969 2nd. Edition) 8122-7044-4.
- Richards, The California Gold Rush and the Coming of the Civil War. (2007) ISBN 0-307-26520-X.
- Roberson, Jere W. "The South and the Pacific Railroad, 1845-1855". The Western Historical Quarterly, Vol. 5, No. 2, (Apr., 1974), pp. 163–186. JSTOR.
- Terrazas, Marcela. "The Regional Conflict, the Contractors, and the Construction Projects of a Road to the Pacific at the End of the War Between Mexico and the United States". Journal of Popular Culture 2001 35(2): 161-169. Issn: 0022-3840 Fulltext: Ebsco, stresses railroad speculation and corruption themes
- Truett, Samuel. "The Ghosts of Frontiers Past: Making and Unmaking Space in the Borderlands". Journal of the Southwest. Volume: 46. Issue: 2. 2004. pp: 309+. online edition
- US Geological Survey USGS Public Lands Survey Map including survey township (6 mile) lines
- Map of proposed Arizona Territory. From explorations by A. B. Gray & others, to accompany memoir by Lieut. Mowry U.S. Army, Delegate elect. with some proposed railroad routes Medium-sized JPG Zoom navigator
- National Park Service Map including route of the Southern Pacific railroad finally built in the 1880s
- US Department of State - Gadsden Purchase, 1853-1854, Office of the Historian
- 3-cent commemorative stamp showing small version of northeast boundary of Purchase - i.e. claiming more territory for U.S. pre-Purchase
- "Gadsden Purchase, The". New International Encyclopedia. 1906.