Interstate 270 Colorado

East End
West End


Interstate 270 angles northwest from Interstate 70 by the Stapleton community in Denver through Commerce City and Interstate 25 by a commerce park area in southern Adams County. The freeway serves commuters west to Westminster and Boulder via connections with U.S. 36 and northeast Denver and Aurora beyond the east end with I-70.

On April 7, 2000, the Route Numbering subcommittee of AASHTO approved the extension of Interstate 270 from I-76 northwest to I-25. The freeway accommodates six lanes of traffic between I-25 and I-76, and just four southeast to I-70. Together with Interstate 76 west to Arvada and Wheat Ridge, I-270 provides a bypass of the oldest section of Interstate 70 through north Denver.


Preliminary numbering for the freeway connecting I-80S (now I-76) and Stapleton International Airport in Denver identified the loop as Interstate 425. The designation was changed to Interstate 270 by AASHO on February 26, 1959.1 Construction of the freeway began on December 12, 1965, with $2.7 million in projects including bridges over Dahlia Street, the Quebec Street overpass, and spans for I-270 over Interstate 70. The initial three miles opened to traffic northwest from I-70 to Vasquez Boulevard (U.S. 6-85). Further work on the two mile link between U.S. 6-85 and I-80S followed with completion on October 23, 1970.2

Construction on the extension west to U.S. 36 (Boulder-Denver Turnpike) and Interstate 25 started in April 1993. Coupled with work to extend Interstate 76 from I-25 to Pecos Street, Phase I work built an eastbound bridge for I-270 over I-25 and rebuilt the U.S. 36 east to I-25 north and southbound ramps. The $11.4 million phase was completed in June 1994. Subsequent construction started in June 1996 for westbound I-270 bridges over Washington Street and I-25, and a bridge connecting I-25 north with U.S. 36 west. Costing $12 million, that construction ran through May 1998.2

Costing $12 million, additional work from July 1997 to December 1998 built the I-270 westbound bridge over Clear Creek with associated work for U.S. 36 over Broadway and the I-25 southbound ramp to U.S. 36 west. The westbound extension of Interstate 270 was completed in February 2000 as part of an $19 million improvement project for I-25 and U.S. 36 from June 1998 to June 2001.2

Route Information

  • East End – Denver, CO

  • West End – Commerce City, CO

  • Mileage – 6.61

  • Cities – Denver, Commerce City

  • JunctionsI-25 I-76 I-70

Source: December 31, 2017 Interstate Route Log and Finders List

Short segments of Interstates 80S, 225 and 270 were opened to traffic across the Denver metropolitan area by 1968.
The original configuration of Interstate 270 in 1986. Exit numbers along the freeway remain unchanged today, despite the addition of one mile.

Further east on the original section, the bridges over U.S. 6-85 (Vasquez Boulevard) were replaced from March 1999 to June 2000 at the cost of $6.2 million. Ongoing work ($8.5 million). completed the eastbound lanes of I-270 from I-25 to York Street from October 1999 to March 2002. The trumpet interchange joining Interstates 76 and 270 was also upgraded through a series of projects. $21 million in work between June 2000 and August 2003 rebuilt ramps from I-270 to both directions of I-76, and constructed seven spans at the exchange.2

A new flyover was added from Interstate 25 south to I-270 & U.S. 36 east as part of an overall I-25 reconstruction project between 84th Avenue and I-76. The $21 million project ran from March 2004 to November 2005. A $15 million flyover project added the movement from I-270 east to I-76 east.2

Highway Guides

East End I-70 US 36 – Denver, Colorado

Perspective from Interstate 270 east
Interstate 270 converges with Interstate 70 east at a wye interchange in the Stapleton area of northeast Denver. Exit 5 separates from the ending freeway for Central Park Boulevard. Photo taken 08/11/16.
An end Interstate 270 shield stands above the departing off-ramp (Exit 279) from I-70 east to Central Park Boulevard. Photo taken 08/11/16.
Two lanes of traffic merge onto Interstate 70 east below Central Park Boulevard. The exchange opened here in October 2011. Central Park Boulevard serves the residential redevelopment of what was Stapleton International Airport. Photo taken 08/11/16.
Historic perspective from Interstate 270 east
Nearing the merge point with Interstate 70 east on I-270 prior to construction of the Central Park Boulevard interchange. Motorists continuing east meet Havana Street in industrial areas of Stapleton at Exit 280. Photo taken by Dale Sanderson (04/01).
Historic perspective from Interstate 70 west
What was previously the 0.75 mile approach to Interstate 270 west is now the location where Exit 279A departs for the freeway west to I-25 and U.S. 36. Construction of Central Park Boulevard (Exit 279B) changed the traffic pattern by 2011. Photo taken 02/02.
Westbound Interstate 70 at the original split with I-270 and hidden U.S. 36 at what was Exit 279. Traffic to I-270 west now combines with an on-ramp from Central Park Boulevard before turning north below Quebec Street (former Colorado 35). Photo taken by Dale Sanderson (04/01).

West End I-25 US 36 – near Commerce City, Colorado

Perspective from Interstate 270 west
Interstate 270 west connects with I-25 north two miles west of the Colorado 265 (Brighton Boulevard) underpass. There is no direct connection to I-25 south; insteads motorists are directed onto I-76 west for its ramp to Denver. Photo taken 04/22/17.
Interstate 270 leaves Commerce City across the South Platte River to meet Interstate 76 (Exit 1). The freeway was extended west from here to Interstate 25 (Exit 0) in 2000. Photo taken 04/22/17.
All traffic to Interstate 76 departs from I-270 in unison at Exit 1. The freeway mainline advances west 1.25 miles to the northbound ramp for Fort Collins and Cheyenne, Wyoming. Photo taken 08/11/16.
Completion of Interstate 270 west in 2000 provided a seamless link for U.S. 36 west onto the Denver-Boulder Turnpike. Prior to this connection, U.S. 36 navigated west on I-76 and north on I-25 to continue northwest to Boulder. Photo taken by Dale Sanderson (04/01).
U.S. 36 emerges from its hidden overlap with I-270 at the systems interchange with Interstate 25. The Boulder-Denver Turnpike takes U.S. 36 northwest to Westminster, Broomfield, Louisville and Superior. Photo taken 08/11/16.
CDOT inventories only one route on implied concurrences. The mileage of U.S. 36 from Strasburg west along I-70, and Denver northwest along I-270, is factored into the mileage of Interstate highway. The Denver-Boulder Turnpike is a part of Route 036B, which is the second independent stretch of U.S. 36 inventoried in the state. Photo taken by Dale Sanderson (04/01).
Perspective from U.S. 36 east
U.S. 36 (Denver-Boulder Turnpike) east becomes Interstate 270 east at the junction with Interstate 25. A begin shield appears as Exit 0 loops onto I-25 north toward Fort Collins. Photo taken 08/11/16.
Historic perspective from Interstate 76 east
Until March 2002, Interstate 270 began from Interstate 76 at Exit 6. Work at the former trumpet interchange between the two freeways continued through August 2003. Photo taken by Dale Sanderson (04/01).
Historic perspective from Interstate 76 west
Approaching Interstate 270 and U.S. 36 on I-76 westbound. Signs still referenced the western extension of I-270 as a Future route. Photo taken 02/02.


  1. Summers, Stephen “Interstate Numbering AASHTO and FHWA.” Online posting. April 18, 2003. news misc.transport.road.
  2. Interstate 270 – 50th Anniversary of the Interstate System. Colorado Department of Transportation (CDOT).

Page updated May 12, 2017.