Interstate 270 Colorado

Interstate 270 Colorado
near Commerce City, CO ↔ Denver, CO•6.61 miles

Overview

Interstate 270 angles northwest from I-70 by the Stapleton community in Denver through Commerce City to I-25 by a commerce park area at Welby 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.

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 I-70 through north Denver.

Mileage by State

Colorado6.61 mi

Data Sources

December 31, 2021 Interstate Route Log and Finders List

History

Preliminary numbering for I-270 connecting I-80S (now I-76) and Stapleton International Airport identified it as part of Route A25, a circumferential highway around the east side of Denver along with what became I-225. Communication between the Colorado Department of Highways and the American Association of State Highway Officials (AASHO) in 1958/59 resulted in subsequent suggestions. The first proposal renumbered I-A25 as I-E25, as it would provide an eastern bypass for Interstate 25.

The Colorado Department of Highways then outlined partitioning I-25E into I-225 for the loop south from I-70 through Aurora, and I-425 for the connection northwest from I-70 to I-25 via Commerce City. The designation changed to Interstate 270 once the planned west end of I-80S was changed from a point along I-70 in Denver northward to I-25 over the westernmost section of I-425. This was approved 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

Denver, CO - 1969 Map
Short segments of I-80S, I-225 and I-270 were opened to traffic across the Denver metropolitan area by 1968.
I-270 Commerce City, CO - 1986 Map
The original configuration of Interstate 270 in 1986. Exit numbers along the freeway remain unchanged today, despite the addition of one mile.

Construction on the extension west to U.S. 36 (Boulder-Denver Turnpike) and Interstate 25 started in April 1993. Coupled with work to lengthen I-76 from I-25 to Pecos Street, Phase I 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 the westbound I-270 bridges over Washington Street and I-25, and a bridge connecting I-25 north with U.S. 36 west. That construction ran through May 1998 and cost $12 million.2

Costing $12 million, additional work from July 1997 to December 1998 built the I-270 westbound bridge over Clear Creek with associated construction 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 The American Association of State Highway and Transportation Officials (AASHTO) Route Numbering subcommittee approved extending Interstate 270 northwest from I-76 to I-25 on April 7, 2000.

East End Interstate 70 U.S. 36 ‐ Denver, CO

Interstate 270 U.S. 36 East at Interstate 70

I-270 east at I-70 - Denver, CO

Interstate 270 converges with I-70 east at a wye interchange within the Central Park neighborhood in northeast Denver. Exit 5 separates from the freeway end for Central Park Boulevard. 08/11/16

I-270 east at I-70 - Denver, CO I-270 east at I-70 - Denver, CO I-270 east at I-70 - Denver, CO

Interstate 70 U.S. 36 West at Interstate 270

I-70/US 36 west at I-270 - Denver, CO

Interstate 70 advances west from I-225 and the Montbello neighborhood in Denver to Central Park and I-270 at Exit 279A. 04/22/17

I-70/US 36 west at I-270 - Denver, CO I-70/US 36 west at I-270 - Denver, CO I-70/US 36 west at I-270 - Denver, CO

East End – Past Views

Past Views Gallery (Tap to Expand / Collapse Section)

Interstate 270 at Interstate 70

I-270 east at I-70 - 2001

Nearing the merge point with Interstate 70 east on I-270 prior to construction of the interchange with Central Park Boulevard. I-70/U.S. 36 continues east to Havana Street in industrial areas of Stapleton at Exit 280. Photo by Dale Sanderson (04/01).

I-270 east at I-70 - 2001 I-70/US 36 west at I-270 - 2002 I-70/US 36 west at I-270 - 2001

West End Interstate 25 U.S. 36 ‐ near Commerce City, CO

Interstate 270 U.S. 36 West at Interstate 25

I-270 west at I-76 - Commerce City, CO

Interstate 270 west connects with I-25 north two miles west of the SH 265 (Brighton Boulevard) underpass. There is no direct connection to I-25 south; instead motorists are directed onto I-76 west for its exit to Denver. 04/22/17

I-270 west at I-76 - Commerce City, CO I-270 west at I-76 - North Washington, CO I-270 west at I-25 - North Washington, CO I-270 west at I-25 - Welby, CO I-270 west at I-25 - Welby, CO I-270 west at I-25 - Welby, CO

U.S. 36 East at Interstate 25 Interstate 270

US 36 east at I-25/270 - Twin Lakes, CO

The Denver-Boulder Turnpike along U.S. 36 originates at Boulder, 20 miles to the northwest of the exchange joining I-25/270. U.S. 36 east transitions onto I-270 east beyond I-25. 04/23/17

US 36 east at I-25/270 - Twin Lakes, CO US 36 east at I-25/270 - Twin Lakes, CO US 36 east at I-25/270 - Twin Lakes, CO US 36 east at I-25/270 - Welby, CO

Interstate 25 South at Interstate 270 U.S. 36

I-25 south at I-270/US 36 - Thornton, CO

Interstate 25 travels south toward I-270 east and U.S. 36 (Denver-Boulder Turnpike) west through the city of Thornton. 04/23/17

I-25 south at I-270/US 36 - Thornton, CO I-25 south at I-270/US 36 - Thornton, CO I-25 south at I-270/US 36 - Thornton, CO I-25 south at I-270/US 36 - Sherrelwood, CO I-25 south at I-270/US 36 - Sherrelwood, CO I-25 south at I-270/US 36 - Sherrelwood, CO

West End – Past Views

Past Views Gallery (Tap to Expand / Collapse Section)

Interstate 270 West at Interstate 25 U.S. 36

I-270 west at I-25/US 36 - 2001

CDOT inventories only one route on implied concurrences. U.S. 36 along I-70 west from Strasburg to Denver and on I-270 is factored into the mileage of the respective 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 by Dale Sanderson (04/01).

Interstate 76 at Interstate 270

I-76 east at I-270 - 2001

Until March 2002, Interstate 270 began at I-76 (Exit 6). Work at the former trumpet interchange between the two freeways continued through August 2003. Photo by Dale Sanderson (04/01).

I-76 east at I-270 - 2001 I-76 west at I-270 - 2002

References

  1. Summers, Stephen "Interstate Numbering AASHTO and FHWA." Online posting. April 18, 2003. news misc.transport.road.
  2. Colorado Department of Transportation (CDOT). Interstate 270 - 50th Anniversary of the Interstate System. Retrieved from https://www.codot.gov/about/CDOTHistory/50th-anniversary/interstate-270.html
Updated November 12, 2020