Interstate 225

The southern end of I-225 begins at an interchange with Interstate 25, as a typical four lane interstate with a 65 mph speed limit. The road heads northeastward through southern Denver,[3] and after exits with DTC Boulevard and Yosemite Street in Greenwood Village,[4] the road becomes six lanes with an auxiliary lane in each direction 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,[5] where it turns northward, maintaining six through lanes and auxiliary lanes at each exit, and a 65 mph speed limit to its northern terminus at I-70,[6] and has upgraded exits at Iliff Avenue, Mississippi Avenue, Alameda Avenue, and 6th Avenue (also signed as State Highway 30).[7] 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).[7] After the exit, I-225 enters Adams County, continuing through the city of Aurora. The route then crosses a railroad[8] and continues north, where it interchanges with Interstate 70.[1] 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 westbound I-70 to southbound I-225 ramp.[5]

The Dayton RTD station in Aurora is located in the center of Interstate 225.

Construction on I-225 began in May 1964 at Interstate 70. A section from Colfax Avenue to Sixth Avenue was opened in 1966. Five years later, a segment between Mississippi Avenue and Parker Road was opened, and construction began on another segment south of Parker Road, completed in May 1975. The rest of the route between Yosemite Street and Interstate 25 was completed in May 1976.[2] The portion from I-25 to SH 83 / Parker Road was rebuilt as part of the T-REX Project completed in 2006.[9] The highway was later widened between Parker Road and Mississippi Avenue to six lanes, as part of a project to widen the entire freeway to I-70; construction on this portion took place between May 2012 and November 2014.[10] Two infill interchanges have opened since the highway was completed – Alameda Avenue in 2002 and 17th Place in 2013.

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