In March, Francisco Madero led 130 men at the Battle of Casas Grandes in Chihuahua. The rebels lost the battle, but later the federals retreated which left Madero's army in control. Madero then began smuggling arms and ammunition on a large scale from across the border.
On 16 March, rebel saboteurs in Ciudad Juarez bombed the barracks and homes of the Mexican Army garrison. A large nitroglycerin explosion was seen on the American side of the border. Two days later, a large cannon which sat in the town square of El Paso, Texas disappeared and was presumably taken to Ciudad Juarez.
Maderista rebels fought federal troops loyal to Porfirio Diaz at Agua Prieta, Sonora in April. United States troops across the border in Douglas, Arizona were attacked by Mexican forces and in response the Americans intervened which left the rebels in control of the town.
Madero's rebels under Pancho Villa and Pascual Orozco attacked federal forces at the major Second Battle of Ciudad Juarez from 7 April-10 May. The American garrison of El Paso, Texas exchanged fire with rebels resulting in minor casualties on both sides.
Porfirio Diaz exiled. Francisco Madero becomes President of Mexico and calls for an end to warfare in the country. He offered to pay rebels of different factions but only if they would lay down their arms or join his new federal Mexican Army.
United States Army continues garrisoning American border towns.
General Pasqual Orozco rebels against President Madero and begins a campaign in the Mexican border state of Chihuahua. Madero responds by sending an army which defeated Orozco's troops in thee major battles. Villa rebels from the Madero government soon after.
Federal Mexican forces of President Francisco Madero establish Fort Tijuana along the international border with California in response to the Magonista campaign.
On 9 April, the Tampico Affair, an incident in Tampico between United States Navy sailors and Mexican troops, occurred. It resulted in the severing of diplomatic relations between Mexico and the United States.
The longest battle of the Mexican Revolution was fought at Naco, Sonora, across the border from Fort Naco and Naco, Arizona. Pancho Villa's men attacked General Obregon's garrison on 17 October. During the 119 following days of siege warfare Villa was defeated. Also during the battle several United States Army Buffalo Soldiers stationed in Naco, Arizona were wounded by rebels shooting into their camp. Eight men were wounded but they did not return fire and were later recognized for their good discipline.
Pancho Villa and Emiliano Zapata capture Mexico City but soon after are forced to retreat by Alvaro Obregon's army.
Carrancistas draft the Plan de San Diego, an operation to overthrow the American state governments of Texas, New Mexico, Arizona, and California by starting a race war. The plan was discovered by the Americans after a Carrancista leader was arrested in Texas though some fighting did occur in the form of raids, launched by rebels into Texas territory.
Pancho Villa attacks General Obregon's Constitutionalist garrison at Nogales, Sonora. Villa initiates a siege but over time is defeated due to the lack of artillery and insufficient supplies. During the siege the United States 12th Infantry garrison of Nogales, Arizona was attacked by Villistas and in turn skirmished for a half hour. Only one American was killed along with several of Villa's rebels.
Villistas and Constitutionalists fought again at Agua Prieta in November. Later, Villa attributed his defeat to large searchlights used during the battle by the United States Army garrison of Douglas, Arizona. The battle ended in defeat for Villa and led to the more disastrous Battle of Hermosillo on 15 November. At this time, Villa's forces pillaged the city instead of fighting the garrison, resulting in a repulse. Also at this time Constitutionalist forces were allowed access to American railways for troop movement.
Now losing the war, Pancho Villa decided to raid Columbus, New Mexico for supplies on March 9, 1916. The raid did not go as planned and Villa's 500 cavalrymen were defeated by over 300 United States infantry and cavalry who were stationed in a border fort outside of town. Columbus was heavily damaged by the Villistas who burned several of the town's buildings. Sixty to eighty Villistas were killed along with over a dozen American troops and civilians.
In response to the attack on Columbus, American President Wilson ordered General John J. Pershing to proceed into Mexico with over 5,000 men to capture or kill Pancho Villa, thus beginning the Pancho Villa Expedition.
On 5 May, Villa's rebels attacked two more American border towns, Glenn Springs, Texas and Boquillas. Over 200 men under Rodriguez Ramirez and Natividad Álvarez crossed the Texas border with the intention of capturing supplies. At Glenn Springs, a United States Army squad of nine men resisted the Villista attack for several hours but eventually the raiders set fire to the adobe building the Americans were held up in and forced the 14th Infantry men to retreat. Three of the United States troops were killed and four others were wounded. One young American boy was also killed by the Mexicans. At Boquillas, 12 mi (19 km) from Glenn Springs, the Americans there captured Alvarez and discovered he was a Lieutenant Colonel in Pancho Villa's Division del Norte and was a veteran of the Battle of Celaya.
The raiders of Glenn Springs and Boquillas took two captives with them when they withdrew across the border. Jesse Deemer and Monroe Payne who were later rescued by American Army forces during a small cavalry expedition into Mexico. The expedition of eighty men, two wagons and a car began on 8 May from Marathon, Texas and was under the command of ColonelFrederick W. Sibley and Colonel George T. Langhorne. The rebels were held up at El Pino, Chihuahua and at first Colonel Langhorne negotiated for the release of the two Americans and when this failed he ordered his men to embark his personal car and head for El Pino. Upon their arrival the Villistas fled and Deemer and Payne were freed. During the operation which ended on 21 May, five Mexicans were killed in skirmishes with no American losses.
President Wilson orders the National Guard to reinforce the United States Army garrisons at the border line. By August, an estimated 117,000 guardsmen were stationed along the border in Texas, New Mexico, Arizona and California.
On 12 April, American forces and Carrancistas fight the Battle of Parral in Chihuahua. When United States troops under MajorFrank Tompkins attempted to leave the city of Parral, they were attacked by Carrancista riflemen. The Americans returned fire, and over the course of several hours 45 Mexicans lay dead along with two Americans. The engagement marked the furthest penetration into northern Mexico by American forces, Parral is over 500 miles from the border.
In June, Buffalo Soldiers of the 10th Cavalry suffered a defeat at the Battle of Carrizal. Federal Mexican troops attacked 100 cavalrymen when they attempted to enter the town of Carrizal. The most famous battle of the Border war was fought and ended with the deaths of 45 Mexicans and 16 Americans. Forty-four other Mexicans and Americans were wounded.
Raids on American border towns continued during and for years after the Pancho Villa Expedition. On 15 June, raiders killed four American soldiers at San Ygnacio, Texas. On 31 July, another soldier and a United States customs inspector were killed in a second raid. During both engagements, Mexicans were killed or wounded but their casualties are not known.
Due to the defeat at Carrizal, President Wilson ordered General Pershing to withdraw from Mexico and end the expedition. By January, most of the American expeditionary troops had left Mexican territory and were back at garrison duty along the border.
United States Army Intelligence stationed at Fort Huachuca, Arizona detected a German military presence in Sonora and ordered troops to begin surveillance operations to prepare for war with Mexico. Mexican railways, train stations, and other related enterprises were inspected as possible routes for a large scale American invasion.
Revolutionary Yaquinative Americans established a base in Bear Valley, Arizona to store weapons intended to be smuggled into Mexico. When the base was discovered by the United States Army, Blondy Ryder of the 10th Cavalry was ordered to evict the rebel Yaquis. On 9 January, Ryder's patrol attacked the Yaquis in a small half-hour engagement. The camp was destroyed, one Yaqui was killed, and nine others were captured. The United States Cavalry suffered no casualties.
In mid-August, Lieutenant Colonel Frederick J. Herman received an anonymous message from a Mexican revolutionary about a possible attack on Nogales, Arizona by federal Mexican soldiers and a group of German military advisors. On 27 August, a Mexican suspected of gun smuggling crossed the border into Nogales, Sonora followed by an American Custom agent and two United States Army troops. A Mexican soldier watched the incident and fired on the American agent. The shot was a miss but hit one of the soldiers instead, the remaining two Americans returned fire and killed the Mexican soldier. From there, the incident escalated from a small dispute into the Battle of Ambos Nogales. Reinforcements from both sides rushed to the border to fight, men of the 35th Infantry Regiment called for aid and a squadron of 10th Cavalry under Herman responded. When they arrived they attacked the Mexican positions on top of hills along the other side of the border. The assault was successful and the Mexican troops with their German advisors were defeated. In all, 30-129 Mexicans, two Germans and seven Americans died in the fighting. After the battle, German military activity in Sonora ceased. The Battle of Ambos Nogales became the last major engagement of the Border War.
American and Mexican forces skirmished near El Paso, Texas on 16 June in the battle known as the Battle of Ciudad Juárez. This conflict is singular on the fact that the Mexican army and the American army joined forces to fight the Villistas led by Pancho Villa. It was the second largest battle of the Mexican Revolution involving the United States, and it's considered the last battle of the Border War.