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New Mexico

Interstate 25 - Colorado


Interstate 25 is the main north-south freeway corridor through Colorado. Part of the Camino Real High Priority Corridor, Interstate 25 connects Mexico with Canada via ports at El Paso and a connection with Interstates 15 and 90 to Canada. The freeway is undergoing several improvements as part of this corridor strategy, including the massive T-REX improvement project in Denver, upgrades through Colorado Springs, and planned expansion of the freeway to six lanes along the Front Range.

Once completed in Colorado, Interstate 25 replaced U.S. 87. That route is silently merged with Interstate 25 for most of its length in Colorado. There are a handful of U.S. 87 shields, and a fun game may be to find the three or so shields for U.S. 87 that remain on Interstate 25. U.S. 87 does not appear on any overhead signs in Colorado.

Interstate 25 Colorado Highway Guides


Interstate 25 was the first mainline Interstate highway to be completed in Colorado. It was also the first segment of freeway to be built in Colorado. Known as the Valley Highway (U.S. 87), the first two-mile section of future Interstate 25 began construction in August, 1948, and was completed in 1950. By 1958, the Valley Highway through the Denver metropolitan area was completed, only two years after the Interstate Highway Act was signed by President Eisenhower. Another pre-Interstate section of Interstate 25 that was grandfathered into the system included a 9.2-mile segment of freeway in Pueblo (construction began in 1949 and was completed in 1958). A notable milestone in the construction process was the extension of Interstate 25 into Wyoming on October 11, 1964. This date marked the first occasion when a Colorado Interstate actually crossed state lines and entered another state. A 26-mile segment of Interstate 25 heading north from Wellington opened on that date.



Mileage (Approximate)


Trinidad/Raton Pass

From Raton Pass at New Mexico Line north to south edge of Trinidad

13 miles



Elevated portion, approximately three miles in length

3 miles


Trinidad to Walsenburg

From Trinidad north to Walsenburg. This was the last segment of I-25 to be completed in Colorado ; it was dedicated on 9/21/69

21 miles



Constructed as the Walsenburg Bypass

3 miles


Walsenburg to Colorado City

Connects north end of Walsenburg bypass with Colorado 165 interchange

22 miles


Colorado City

From Colorado 165 interchange in Colorado City north to Pueblo Boulevard

20 miles



Original urban freeway segment of Interstate 25 near downtown Pueblo ; includes 0.6-mile long bridge over Arkansas River

9.2 miles

July 1959

South of Pueblo to Monument

From south of Pueblo to north of Colorado Springs; connected pre-existing segments in Pueblo and Colorado Springs

67 miles


Colorado Springs

Original urban freeway segment of Interstate 25 near downtown Colorado Springs

12 miles

July 1960

Monument Hill

Monument to Larkspur

12 miles


Larkspur to Castle Rock


9 miles


Castle Rock to Denver

Connects Castle Rock with Valley Highway in Denver

25 miles



From Evans Avenue north to 48th Avenue . This urban freeway was first section of Interstate 25 built; it was known as the Valley Highway (U.S. 87)

11.2 miles

November 1958

Denver Northside

From the north end of the Valley Highway (at 48th Avenue ) north to 58th Avenue

0.5 mile


Denver north

From 58th Avenue to Colorado 7

14 miles


Longmont Area

From Colorado 7 to Colorado 66

14 miles


North of Denver

From Colorado 66 to U.S. 34

14 miles


Fort Collins Area

U.S. 34 to (now former) Colorado 68 ( Harmony Road )

8 miles


Colorado 68 to North of Wellington

Harmony Road in Fort Collins to Buckeye Road (at that time, Interstate 25 became continuous from Walsenburg north to Colorado/Wyoming border)

23 miles


North Link

From north of Wellington ( Buckeye Road ) to Colorado-Wyoming Border

17 miles

October 1964

Miscellaneous Interstate 25 Pictures
View of the Colorado Springs skyline as seen from northbound Interstate 25 looking east down Colorado Avenue. Photo taken 11/11/03.
Westbound Lincoln Avenue reaches its junction with Interstate 25 at Exit 193 in Douglas County, south of Denver. Photo taken 08/27/04.
Other Interstate 25/U.S. 87 Pictures
Ramp meters from Colorado 88 onto northbound Interstate 25. Yes indeed, ramp meters have arrived in Denver! Photo taken 02/02/02.
Side view looking east of the Steele Street bridge over Interstate 25/U.S. 87 and the temporary replacement bridge used for pedestrians only. This facility has been replaced with a permanent Steele Street bridge as part of the T-Rex reconstruction project on Interstate 25. Photo taken 02/02/02.
View of temporary pedestrian bridge at Steele Street, looking east. This bridge is gone now that the permanent bridge is back in place. Photo taken 02/02/02.
Many of the older bridges along Interstate 25 have the street name in a small green sign on the bridge so it is visible to traffic passing below. However, while most newer bridges in Colorado do not have similar signage that announce the name of the street passing over the freeway, the new T-Rex bridges have the street names inscribed into the bridges. Photo taken 02/02/02.
This suite of pictures shows the former Steele Street bridge on the day before it was to be demolished overnight by work crews. Photos taken 02/02/02.

Page Updated July 23, 2005.