I-225

Interstate 225
I-225 highlighted in red
Route information
Maintained by CDOT
Length:	11.959 mi (19.246 km)
Existed:	1976 – present
Major junctions
South end:	I-25 / US 87 in Denver
	I-70 Bus. / US 40 / US 287 in Aurora
North end:	I-70 / US 36 in Aurora and Denver
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Colorado State Highways Interstate U.S. State Scenic ← SH 224 SH 227 →

Interstate 225 (I-225) is a connector spur route of Interstate 25 in Colorado. It is the only auxiliary route of Interstate 25, and one of two auxiliary Interstate highways in the state of Colorado. I-225 traverses Aurora and small portions of Denver and Greenwood Village. It runs north from Interstate 25 to Interstate 70. It intersects with Interstate 70 Business/U.S. Highway 40/U.S. Highway 287, known locally as Colfax Avenue. Construction on the freeway began in 1964 and continued progressively through many years until final completion in 1976.

The southern end of I-225 begins at an interchange with Interstate 25, as a typical two lane interstate with a 65 mph speed limit. The road heads northeastward through southern Denver, and after exits with DTC Boulevard and Yosemite Street in Greenwood Village, the road becomes three lanes with a fourth auxiliary lane traversing the Denver/Greenwood Village city limits. With Cherry Creek State Park and Cherry Creek Reservoir on its east side, the highway interchanges with State Highway 83 at the northern boundary of the park. Following the exit at SH 83, the freeway enters Aurora, where it turns northward, maintaining three through lanes, auxiliary lanes at each exit, and a 65 mph speed limit to its northern terminus at I-70, and has upgraded exits at Iliff Avenue, Mississippi Avenue, Alameda Avenue, and 6th Avenue (also signed as State Highway 30). After crossing Sand Creek, the freeway interchanges with Colfax Avenue (also signed as U.S. Highway 40, U.S. Highway 287 and Interstate 70 Business), and then with 17th Place (serving the Anschutz Medical Campus). After the exit, I-225 enters Adams County, continuing through the city of Aurora. The route then crosses a railroad and continues north, where it interchanges with Interstate 70. The northbound ramp to westbound I-70 reenters Denver, and the eastbound I-70 to southbound I-225 ramp originates in Denver but enters Aurora as it passes under the westbound I-70 to southbound I-225 ramp.