Following all of Colfax Avenue, Business Loop I-70 runs alongside U.S. 40 for its 27.47 mile route from Golden to Aurora, and with U.S. 287 east from Federal Boulevard and Sun Valley in Denver. The route is not acknowledged from signs at the west end with I-70, nor on Interstates 25 or 225. CDOT inventories the route solely as U.S. 40 (Route 040C).

Colfax Avenue is named after Schyuler Colfax, an Indiana congressman who passed through Colorado in 1865 and later became Vice President under Ulysses S. Grant. If it were not named for Colfax, it would be 15th Avenue. According to the Denver Rocky Mountain News from June 19, 2000, Colfax Avenue is "the longest continuous commercial thoroughfare" in the United States.

Historically U.S. 36 also used to overlap with U.S. 40 along Colfax Avenue. The route later shifted to a hidden concurrency with both Interstate 70 and 270.

Business Loop I-70 U.S. 40 East
Although not signed from the Interstate 70 eastbound mainline, a shield for Business Loop I-70 does appear at the end of the off-ramp (Exit 259) at County Road 93. 08/11/16
County Road 93 (former Colorado 26) runs north along Dinosaur Ridge to meet Interstate 70 as it emerges from Mount Vernon Canyon. Business Loop I-70 overlaps the county road north to nearby U.S. 40 (Colfax Avenue) east. 08/11/16
U.S. 40 parallels I-70 west through Mount Vernon Canyon to Genesee Park. Eastbound Business Loop I-70 and U.S. 40 loop north into Golden while I-70 travels further south to C-470 by Green Mountain. 08/11/16
Reassurance marker posted after Heritage Road (CR 93) and Heritage Square Amusement Park along Colfax Avenue east on the outskirts of Golden. 08/10/14
Colfax Avenue expands into a four lane, commercial arterial east from the C-470 overpass to Corporate Center Business Park and Interplaza shopping center and U.S. 6 (6th Avenue). Business Loop I-70 & U.S. 40 proceed east from there to cross paths with Interstate 70 at a diamond interchange by the Pleasant View neighborhood in west Lakewood. 08/10/14
Business Loop I-70 & U.S. 40 shield assembly posted after I-70 and ahead of Indiana Street and Colorado Mills mall. 08/10/14
Continuing east from the retail area at Colorado Mills, Colfax Avenue enters the Wide Acres Orchard residential area and intersects Normandy Road south and Youngfield Street. Youngfield Street meanders northeast between the Tanglewood and Applewood Heights subdivisions before turning north along a linear route to Wheat Ridge. Youngfield Street is the historic alignment of Colorado 173. Colorado 173 was a 1930s route extending north to West 64th Avenue along a combination of 44th Avenue and Ward Road. 08/10/14
Colfax Avenue reenters the city of Lakewood east from Youngfield Street. A welcome sign appears after Overhill Road. 08/10/14
The Denver skyline comes into view as Business Loop I-70 & U.S. 40 (Colfax Avenue) lower toward Simms Street. 08/10/14
Shields for Business Loop I-70 & U.S. 40 east posted at Simms Street. The ensuing stretch becomes more commercialized, with big box retail. 08/10/14
Colorado 121 (Wadsworth Boulevard) crosses Colfax Avenue at a commercialized intersection north from the Lakewood city center and south from Wheat Ridge city hall. 08/10/14
Business Loop I-70 U.S. 40 East U.S. 287 South
U.S. 40-287 and Business Loop I-70 travel a viaduct east from their merge across the South Platte River, Interstate 25 and BNSF Railroad tracks to the Auraria neighborhood west of the Denver Central Business District. 08/27/04
Republic Plaza tops out the Denver skyline at 714 feet. 1801 California Street (CenturyLink Tower) comes in second at 709 feet. 08/27/04
Colfax Avenue settles back into the Denver street grid at 7th and Osage Streets by Metropolitan State University of Denver. 08/27/04
Lipan Street stems south from Colfax Avenue into the Lincoln Park neighborhood. The Colorado State Capitol comes into view several blocks to the east of here, on the south side of Colfax Avenue. The building features a golden dome, and the mile-high elevation of 5,280 feet is marked on one of the steps leading to the building. 08/27/04
Speer Boulevard, a major route through metropolitan Denver, follows Cherry Creek to the southeast toward the Golden Triangle and Cherry Creek shopping mall. 08/27/04
Street light replacements along Colfax Avenue through Downtown Denver made by 2012 claimed this shield assembly for Business Loop I-70 and U.S. 40-287 at Welton Street. 08/27/04
Heading east from the Colorado State Capitol, Colfax Avenue passes between the Capitol Hill and North Capitol Hill neighborhoods. 08/27/04
Business Loop I-70 U.S. 40 West U.S. 287 North
Business Loop I-70 & U.S. 40-287 split from Interstate 70 via a wye interchange in east Aurora. 08/11/16
The first confirming shields for Business Loop I-70 & U.S. 40-287 posted along Colfax Avenue westbound. Colfax Avenue lines the boundary between Adams and Arapahoe Counties. 08/11/16
Colfax Avenue constitutes a four lane divided highway west by Aurora Sports Park and the Aurora East community. 08/11/16
Dunkirk Street south from the Aurora Cascades subdivision and Dunkirk Court north from Aurora Sports Park come together at the first traffic light along Business Loop I-70 & U.S. 40-287 west. 08/11/16
Tower Road stems north from Colfax Avenue to industrial areas populated by distribution centers and warehouses to Interstate 70 at Exit 286. A CDOT maintenance facility lines the south side of Business Loop I-70 here. 08/11/16
Colfax Avenue continues west by this set of shields to cross Sand Creek. 08/11/16
Trailblazer signage for I-70 direct motorists west along Colfax Avenue to Interstate 225. 08/11/16
Business Loop I-70 & U.S. 40-287 pass by the Friendly Village of Aurora mobile home park and cross East Branch Highline Canal at a second trailblazer for Interstate 70. 08/11/16
Airport Boulevard constitutes a north-south arterial from Alameda Parkway near the Tollgate Village development to Pena Boulevard, the freeway spur from I-70 to Denver International Airport (DEN). 08/11/16
Commercial strip malls and several small mobile home parks line Colfax Avenue west from Airport Boulevard to Chambers Road. 08/11/16
Laredo Street links Colfax Avenue with the Norfolk Glen subdivision in Adams County and the Apache Mesa and La Vista neighborhoods south in Arapahoe County. 08/11/16
Another non standard trailblazer sign for I-70 precedes the Business Loop I-70 intersection with Chambers Road. 08/11/16
Chambers Road crosses paths with Colfax Avenue north from the Chamber Heights neighborhood and Hinkley High School. The arterial extends north to the Peterson industrial area and Interstate 70. 08/11/16
Sable Boulevard intersects Business Loop I-70 & U.S. 40-287 south from an RV park and north from Chambers Heights. The signal serves an elementary and middle school. 08/11/16
Interstate 225 meets Colfax Avenue next as it parallels Toll Gate Creek and Fitzsimons Parkway by the University of Colorado Anschutz Medical Campus. 08/11/16
A diamond interchange facilitates movements to Interstate 225 from Business Loop I-70 & U.S. 40-287. 08/11/16
Traffic lights operate at a service road just ahead of the northbound on-ramp for I-225. The six lane freeway joins Stapleton in east Denver with Denver Tech Center to the south. 08/11/16
Interstate 225 concludes two miles to the north at Interstate 70. The commuter freeway totals 12.43 miles overall south to I-25. 08/11/16
The north end of I-225 ties into I-70 just west of Pena Boulevard to DEN Airport and three miles east of the split with I-270 west to Commerce City. 08/11/16
Business Loop I-70 U.S. 40 West
Business Loop I-70 & U.S. 40 veer south toward Heritage Road (CR 93) along a rural stretch leading to I-70 and Dinosaur Ridge south of Golden. 11/10/03

Photo Credits:

11/10/03, 08/27/04, 08/10/14, 08/11/16 by AARoads

Connect with:
Interstate 25
Interstate 70
Interstate 225
U.S. 6
State Highway 121 - Wadsworth Boulevard

Page Updated 04-19-2017.

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