Interstate 25 in Colorado
|Maintained by Colorado Department of Transportation|
|Length:||305.040 mi (490.914 km)|
|South end:||I-25 / US 85 / US 87 near Trinidad|
| US 160 in Trinidad
US 160 in Walsenburg
US 50 in Pueblo
US 24 in Colorado Springs
US 85 in Castle Rock
SH 470 / E-470 in Lone Tree
I-225 in Denver
US 285 in Denver
US 85 in Denver
US 6 in Denver
US 40 / US 287 in Denver
I-70 / US 6 / US 85 in Denver
I-76 in North Washington
I-270 / US 36 in Welby
E-470 in Broomfield
US 34 near Loveland
|North end:||I-25 / US 87 near Wellington|
Historical nicknames for this route have included the Valley Highway (through Denver), Monument Valley Highway (through Colorado Springs), and the Pueblo Freeway (through Pueblo). Within El Paso County, the route has been dedicated as the Ronald Reagan Highway. In Pueblo County, the route is called John F. Kennedy Memorial Highway.
Route description 
New Mexico state line to Pueblo 
Following the Santa Fe Trail from New Mexico, Interstate 25 enters Colorado as a typical two-lane Interstate Highway, where its entire route in Colorado lies close to the east side of the Rocky Mountains. The route turns from north to west-northwest as I-25 serves Wootton. After leaving Wootton, I-25 turns back up north and bypasses near the east side of the Trinidad Lake State Park, home of the Trinidad Lake.
Trinidad, a city near the Trinidad Lake, is the first major city that lies along I-25. For the next 30 miles (48 km), I-25 continues north through the rural areas of Colorado until it reaches the small city of Walsenburg, where the business route - I-25 Bus. - junctions with U.S. Highway 160. I-25 then continues in a north-northwest direction until it bypasses the Orlando Reservoir, then turns north from there until it reaches Colorado City. In Colorado City, I-25 interchanges with the east end of the Frontier Pathways Scenic and Historic Byway (SH 165) at exit 74.
After leaving the city, I-25 follows in a north-northeast orientation until it reaches the St. Charles Reservoir just before entering the city of Pueblo, with the first exit within the southern city limits of Pueblo at exit 94. The Arkansas River in Pueblo serves as a feeder to the Lake Pueblo State Park, home of the Pueblo Lake, which is located to the west of the western city limits of Pueblo.
Pueblo to Denver 
After leaving Pueblo, I-25 continues up north with the Union Pacific Railroad line paralleling closely to the route on the right side after interchanging with Porter Draw at exit 106. By exit 119, the Fountain Creek joins along and travels parallel with I-25, and continues all the way to the Fountain Creek Regional Park in Widefield. I-25 gradually turns from a general north direction to the north-northwest and serves the census-designated place of Buttes at exit 122.
As soon as US 85 leaves I-25 at exit 128, I-25 enters the city limits of Fountain. Basically, I-25 serves as the border between the western city limits of Fountain on the east side of I-25 and Fort Carson on the west side. Exit 132 (SH 16) serves the north side of the Fountain Creek Regional Park as well as the entrance to Fort Carson and connects to SH 21 (Powers Boulevard), the eastern bypass for the Colorado Springs metro area. By the time I-25 reaches exit 138, the route crosses into the city limits of Colorado Springs, where the stack interchange with US 24 at exit 139 serves the Evergreen Cemetery and Prospect Lake. I-25 turns west at exit 140, along with the Fountain Creek, where it interchanges with US 85, US 87, and I-25 Bus. I-25 again turns back north again by exit 141. Swinging around the west side of downtown Colorado Springs at Exit 142, and to the north of the city lies the Colorado College, and is served at exit 143 - Uintah Street. Continuing north and northeast, the highway intersects the north terminus of I-25 Bus. and US 85. The interstate leaves Colorado Springs between exits 153 and 156, where I-25 enters the United States Air Force Academy, going through the east side of the territory.
I-25 leaves El Paso County and enters Douglas County at the county line at exit 163 north of Monument. I-25 then continues north through more rural and hilly areas areas east of the Rocky Mountains until reaching Castle Rock at exit 181. I-25 continues through rural Douglas County until interchanging with E-470, the partial beltway of Denver as the toll road serves the Centennial Airport and the much larger Denver International Airport.
After entering Arapahoe County, I-25 cuts through the Denver Technological Center (DTC) between Dry Creek Road and Belleview Avenue (exits 196-199). I-25 enters Denver at the I-225 interchange, a spur that detours motorists to I-70 through Aurora, at exit 200. I-25 turns in an westerly direction between Evans Avenue (Exit 203) and Colorado Boulevard (Exit 204). University of Denver lies just to the south of the interstate at Exit 205. It then turns back north after Exit 207. I-25 curves around the west side of downtown Denver, where it can be accessed by I-70 Bus. at exit 210. I-25 then interchanges with I-70 at exit 214 right before leaving the City and County of Denver. 
Denver to Wyoming state line 
As I-25 leaves Denver, the route continues up north and interchanges with I-76, I-270, and the Denver-Boulder Turnpike (US 36). Due to the complexity of this triangle-shaped interchange, it was known to be one of many malfunction junctions throughout the United States. Beyond that interchange and exit 220, I-25 slips its way through a narrow path between the Badding Reservoir (west side) and the Croke Lake (east side).
At exit 228, I-25 interchanges with the northern termini of E-470 and Northwest Parkway at a stack interchange, with the Larkridge Mall just to the north, served by 160th Avenue (SH 7). As I-25 continues north, it passes through a medley of lakes and reservoirs to the east and north of Fort Collins. Afterwards, the interstate gradually makes a north-northeast turn as it heads for the Wyoming state line.
Ancestors and early freeways 
State Highway 1, an unpaved road, was completed between Denver and Pueblo by 1919. Average travel time between Pueblo and Colorado Springs on this route was approximately 2.5 hours (or a full 8.5 hours from Pueblo to Denver). This route was upgraded with the help of the federal government to become US 85 and US 87 by 1930, now paved in concrete and shortening the travel time between Pueblo and Colorado Springs to just one hour.
The cities of Denver (in 1948) and Pueblo (in 1949) were first to begin building multi-lane highway segments along the route of what would eventually become Interstate 25. Construction follows an earlier segment of the Colorado and Southern Railway. Denver's segment was originally known as the Valley Highway and was completed by 1958. The city of Colorado Springs followed a similar theme with their Monument Valley Freeway, begun in 1955 and completed by July 1960. Pueblo's section — the Pueblo Freeway - was complete by July 1959.
Interstate completion 
As the national Interstate Highway System began to take shape, actual "inter-state" connections began to be made. Wyoming came first in 1964, building a 9-mile (14 km) link north to Cheyenne that was connected to Colorado's 17-mile (27 km) stretch.
Linking to New Mexico in the south would prove more problematic as the planned route had to stretch over Raton Pass, and its accompanying 1,800-foot (550 m) elevation change, within just 13 miles (21 km). Once again, US 85 and US 87 were used, but it had to be re-graded in places to meet Interstate design guidelines. Construction began in 1960, with a link to the city of Trinidad completed by 1963. The Trinidad Segment (as CDOT now calls the Raton Pass span) was not fully completed until 1968.
The final segment of the Colorado portion of Interstate 25, connecting the cities of Walsenburg and Trinidad, was completed during 1969. This meant that four lanes of high-speed, nonstop freeway were finally open for a full 305 miles (491 km) from New Mexico north to Wyoming.
Modern expansion 
As both population and traffic increased in Colorado during the 1990s and 2000s, the Colorado Department of Transportation has planned and completed major improvements for the city corridors along I-25.
T-REX (Denver) 
The first of these was Transportation Expansion (T-REX), which widened and expanded nearly 17 miles (27 km) of both I-25 and the I-225 bypass in the Denver Metropolitan Area as well as adding various pedestrian and aesthetic improvements. T-REX was also instrumental in expanding Denver's RTD light rail lines to connect outlying communities beyond the city and county of Denver, adding 19 miles (31 km) of new routes.
Starting in early 2004, the T-REX project was completed during 2006 at a cost of US$1.67 billion, under its projected budget and two years ahead of its originally scheduled conclusion. It has been hailed as a "model for other cities to follow" and "ahead of the curve nationally" by federal transportation and transit authorities.
COSMIX (Colorado Springs) 
As T-REX began to wrap up, CDOT's next major effort began with Colorado Springs Metro Interstate Expansion (COSMIX). It could be argued that COSMIX was even more important to Colorado's interests than T-REX had been, since the Colorado Springs corridor of I-25 had seen immense growth over the past four decades, and experienced major choke points all along the 16-mile corridor from Exit 135 (Academy Blvd) in the south to Exit 151 (Briargate Blvd) in the north. Originally carrying around 8500 vehicles per day in 1960, usage of the former Monument Valley Freeway had grown to an average of 100,000 vehicles per day by 2005.
The major goals of COSMIX, which began in 2005 and was completed a year and four days ahead of schedule at the very end of December, 2007, were a general expansion and widening of the corridor to three lanes in each direction throughout the city, as well as the reconstruction of two main interchanges (at Bijou Street near downtown Colorado Springs, and at Rockrimmon Boulevard and North Nevada Avenue in the city's growing north side). Originally estimated at $225 million, on delivery COSMIX cost only $150 million, approximately $20 million of which involved land acquisition costs. With respect to schedule and budget, then, COSMIX proved a superbly successful project, the result of the decision by the project manager and project engineer, both young women, to negotiate with CDOT for six months' extra detail planning time up front. Their efforts paid off in an effective reduction of the overall work schedule by 18 months and 4 days.
Though CDOT's role in COSMIX was complete, the City of Colorado Springs continued its own independent project to rebuild the Cimarron Street (US 24) bridge and interchange. This work was functionally complete (allowing limited traffic) by May 2008, with full completion achieved by September 2008.
Reconstruction of the aging Trinidad Segment was completed which rebuilt bridges and upgraded the highway to modern Interstate design standards. Construction began with demolition and reconstruction of the bridges during 2007, and the remaining viaduct reconstruction completed by 2011.
CDOT will soon begin construction along I-25 in northern El Paso county, which will expand the congested freeway from 4 to 6 lanes in the north Colorado Springs area. The project will consist of expansion of 11 miles between Academy Boulevard (Exit 150 and the northern terminus of the previous COSMIX project) and SH 105 in Monument (Exit 161). The area has seen tremendous growth in recent years and becomes a congested road much of the time. 
Lane Configuration 
Total through lane count on highway
- 4 lanes from New Mexico border to Circle Drive (exit 138)
- 8 lanes from Circle Drive to Nevada Avenue/Tejon Street (exit 140)
- 6 lanes from Nevada Avenue to Academy Boulevard (exit 150)
- 4 lanes from Academy Boulevard to Plum Creek Parkway (exit 181)
- 6 lanes from Plum Creek Parkway to Founders Parkway (exit 184)
- 8 lanes from Founders Parkway (exit 184) to RidgeGate Parkway (exit 192)
- 6 lanes from RidgeGate Parkway to Dry Creek Road (exit 196)
- 10 lanes from Dry Creek Road to I-225 (exit 200)
- 8 lanes from I-225 to I-76 (exit 216B)
- 6 lanes from I-76 to SH 66 (exit 243)
- 4 lanes from SH 66 to Wyoming border
Exit list 
|11.013||17.724||11||Santa Fe Trail – Starkville|
|Trinidad||13.000||20.921||13A||Van Buren Street|
|13.311||21.422||13B||SH 12 west (Main Street) – Cuchara, La Veta|
|14.859||23.913||15||SH 239 north / US 160 east / Goddard Avenue||South end of US 160 overlap|
|17.728||28.530||18||El Moro Road|
|Walsenburg||49.000||78.858||49||I-25 Bus. north to US 160 west – Walsenburg, Alamosa|
|50.054||80.554||50||SH 10 east (US 160 west) – La Junta||North end of US 160 overlap|
|52.321||84.202||52||I-25 Bus. south / SH 69 west to US 160 west – Gardner, Westcliffe|
||Colorado City||71.264||114.688||71||Graneros Road|
|74.367||119.682||74||SH 165 west – San Isabel, Colorado City, Rye|
|77.267||124.349||77||Abbey Road, Hatchet Ranch Road|
|87.921||141.495||88||Burnt Mill Road|
|Pueblo||94.769||152.516||94||SH 45 north (Pueblo Boulevard)|
|95.901||154.338||96||Minnequa Avenue, Indiana Avenue|
|96.673||155.580||97A||Central Avenue to Northern Avenue|
US 50 Bus. east – La Junta
|98.545||158.593||98B||To SH 96 / 1st Street|
|98.806||159.013||99A||To SH 96 / 6th Street||Southbound exit and northbound entrance (from Bradford Avenue)|
|99.334||159.863||99B||13th Street, Santa Fe Avenue|
|99.950||160.854||100A||US 50 east – La Junta, Pueblo Memorial Airport||South end of US 50 overlap|
|101.389||163.170||101||US 50 west (SH 47 east) – Canon City, Royal Gorge||North end of US 50 overlap|
|Pueblo West||108.000||173.809||108||Purcell Boulevard – Pueblo West|
|115.831||186.412||116||County Line Road|
||118.843||191.259||119||Rancho Colorado Boulevard|
|121.459||195.469||122||Pikes Peak International Raceway|
|124.564||200.466||125||Ray Nixon Road|
|Fountain||127.860||205.771||128||US 85 north – Fountain||North end of US 85 overlap|
|131.653||211.875||132||SH 16 (Mesa Ridge Parkway) to SH 21 (Powers Boulevard) – Fort Carson, Fountain||Signed as exits 132B (west) and 132A (east)|
|Stratmoor||135.262||217.683||135||SH 83 (Academy Boulevard) – Colorado Springs Municipal Airport|
|Colorado Springs||137.752||221.690||138||Lake Avenue, Circle Drive|
|138.742||223.284||139||US 24 east (Martin Luther King Jr. Bypass) – Limon||South end of US 24 overlap|
|140||SH 115 south (Nevada Avenue, Tejon Street) – Cañon City|
|141.139||227.141||141||US 24 west (Cimarron Street) – Manitou Springs, Pikes Peak||North end of US 24 overlap|
|141.849||228.284||142||Bijou Street – Downtown Colorado Springs|
|144.622||232.747||145||SH 38 east (Fillmore Street)|
|146.074||235.083||146||Garden of the Gods Road|
|148||Nevada Avenue (US 85 south), Corporate Drive, Rockrimmon Boulevard||South end of US 85 overlap|
|150.303||241.889||150||North Academy Boulevard|
|152.899||246.067||153||To SH 21 (Powers Boulevard) / InterQuest Parkway – Black Forest|
|Air Force Academy||155.930||250.945||156A||North Gate Boulevard|
|155.930||250.945||156B||North Entrance Air Force Academy|
|Monument||160.763||258.723||161||SH 105 – Monument, Palmer Lake|
|163.321||262.840||163||County Line Road – Palmer Lake|
|171.820||276.517||172||Upper Lake Gulch Road|
|172.307||277.301||173||Larkspur||Southbound exit and northbound entrance|
|Castle Rock||180.808||290.982||181||Plum Creek Parkway|
|181.853||292.664||182||Wilcox Street, Wolfensberger Road|
|184.212||296.460||184||US 85 north (Meadows Parkway) / SH 86 east / Founders Parkway||North end of US 85 overlap|
|186.935||300.843||187||Happy Canyon Road|
|188.486||303.339||188||Castle Pines Parkway|
|Lone Tree||192.096||309.149||192||RidgeGate Parkway||Opened on May 20, 2009|
|194.314||312.718||194||SH 470 west / E-470 east – Grand Junction, Limon|
|Lone Tree–Centennial line||195.130||314.031||195||County Line Road|
||Centennial||196.141||315.658||196||Dry Creek Road|
|197.188||317.343||197||SH 88 east (Arapahoe Road)||South end of SH 88 overlap|
|Greenwood Village||198.292||319.120||198||Orchard Road|
|199.384||320.877||199||SH 88 west (Belleview Avenue)||North end of SH 88 overlap|
|City and County of Denver
||200.093||322.018||200||I-225 north to I-70 – Limon, Aurora|
|201.578||324.408||201||US 285 south / SH 30 east (Hampden Avenue)|
|204.037||328.366||204||SH 2 (Colorado Boulevard)|
|205.919||331.395||206||Downing Street, Washington Street, Emerson Street|
|206.968||333.083||207A||Lincoln Street, Broadway|
|207.488||333.920||207B||US 85 south (Santa Fe Drive)||South end of US 85 overlap|
|208||SH 26 (Alameda Avenue)||Northbound exit is via exit 207B|
|209.210||336.691||209||US 6 (6th Avenue) – Lakewood||South end of US 6 overlap; signed as exits 209A (east) and 209B (west)|
|210.310||338.461||210A||US 40 (Colfax Avenue, I-70 Bus./US 287) – Downtown Denver|
|210.415||338.630||210C||Auraria Parkway||Northbound exit and southbound entrance|
|210.532||338.818||210B||17th Avenue||Southbound exit (to 20th Avenue) is via exit 211|
|211.464||340.318||212||Speer Boulevard – Downtown Denver||Signed as exits 212A (south) and 212B (north)|
|212.769||342.419||213||Park Avenue, West 38th Avenue|
|214A||I-70 (US 6 east/US 85 north) – Limon, Grand Junction||North end of US 6 / US 85 overlap; locally known as The Mousetrap|
||213.964||344.342||214B||48th Avenue||Southbound exit only|
|216||I-76 – Grand Junction, Fort Morgan||Signed as exits 216A (east) and 216B (west)|
|216.779||348.872||216B||70th Avenue||Northbound exit and southbound entrance|
|217.006||349.237||217||I-270 east / US 36 – Limon, Aurora, Boulder||Signed as exits 217A (west) and 217B (east) southbound|
|Thornton||218.463||351.582||219||84th Avenue – Federal Heights|
|Northglenn||221.027||355.708||221||104th Avenue – Northglenn||Former SH 44|
|Northglenn–Westminster line||223.049||358.963||223||SH 128 west (120th Avenue)|
|City and County of Broomfield
||227.745||366.520||228||E-470 / Northwest Parkway – Limon, Broomfield|
|229.107||368.712||229||SH 7 – Lafayette, Brighton|
|235.114||378.379||235||SH 52 – Dacono, Frederick, Fort Lupton|
|240.114||386.426||240||SH 119 west – Firestone, Longmont|
|243.148||391.309||243||SH 66 – Longmont, Lyons|
|Johnstown||250.241||402.724||250||SH 56 west – Berthoud|
|252.261||405.975||252||SH 60 east – Johnstown, Milliken|
||254.216||409.121||254||To SH 60 west – Campion|
|255.272||410.820||255||SH 402 west – Loveland|
|257.305||414.092||257||US 34 – Greeley, Loveland|
|Loveland||259.309||417.317||259||Crossroads Boulevard – Fort Collins-Loveland Airport|
|262.298||422.128||262||SH 392 east – Windsor|
|Fort Collins||265.314||426.981||265||Harmony Road|
|269||SH 14 – Fort Collins, Ault||Signed as exits 269A (east) and 269B (west)|
|271.373||436.733||271||Mountain Vista Drive|
|Wellington||277.884||447.211||278||SH 1 south – Wellington|
|281.338||452.770||281||Owl Canyon Road|
- Colorado Department of Transportation, Highway Data, accessed October 2007: note that not every interval between mileposts is exactly a mile, explaining why more exits than expected are at the exact milepost
- Ronald Reagan Presidential Foundation & Library[dead link]
- "Interstate 25". Dot.state.co.us. Retrieved 2011-11-27.
- Sierra County Economic Development Organization. "Transportation and Highways". Retrieved February 2008.[dead link]
- Rand McNally (2006). The Road Atlas (Map). p. 32.
- Google Maps street maps and USGS topographic maps, accessed February 2008 via ACME Mapper
- Kuennen, Tom, ed. Interstate 50: 50 Years of the Dwight D. Eisenhower National System of Interstate and Defense Highways. 2006: Faircount. pp 118-119. ISBN unavailable.
- "Metro Denver's multi-modal T-REX takes last step - Metro Denver Economic Development Corporation". Metrodenver.org. Retrieved 2011-11-27.
- Kuennen, Tom, ed. Interstate 50: 50 Years of the Dwight D. Eisenhower National System of Interstate and Defense Highways. 2006: Faircount. pp 118-119. ISBN unavailable.
- "Progress of Project". Cosmixproject.com. Retrieved 2011-11-27.[dead link]
- Pikes Peak Transportation[dead link]
- FHU and Lawrence Construction for the Colorado Department of Transportation (CDOT). "I-25 Trinidad under construction - Home". coloradodot.info. Retrieved 2012-12-23.
- "I-25 North Design Build (Colorado Springs) — CDOT". Coloradodot.info. Retrieved 2013-01-28.
- "RidgeGate Parkway Interchange Brings Traffic Relief to Douglas County". Southeast Connections. June 2009. Retrieved 2011-11-27.
- Colorado Department of Transportation (CDOT)
- COSMIX (CDOT project; website no longer being updated)[dead link]
- South I-25 Corridor: Lincoln Avenue through Castle Rock (CDOT project)[dead link]
- The North Forty (CDOT project)
- I-25 Trinidad (CDOT project)
- The New Pueblo Freeway (proposed CDOT project)