Interstate 225 (I-225) is an auxiliary Interstate Highway in the U.S. state of Colorado. The freeway is a connector spur route of I-25 that acts as an eastern bypass in the Denver metropolitan area and serves Aurora. It also provides direct access to Denver International Airport for the Denver Tech Center and the southern suburbs of Denver. I-225 is one of the two existing auxiliary Interstate Highways in Colorado and it is the only auxiliary route of I-25, as there are no auxiliary routes for I-25 in New Mexico and Wyoming. The route begins at I-25 in the Denver Tech Center and runs north to I-70 north of Aurora. It interchanges with State Highway 83 (SH 83), SH 30 and I-70 Business/US 40/US 287, known locally as Colfax Avenue. The freeway was first proposed in the 1950s along with the first Interstate Highways within Denver. Construction did not begin until 1964 at the I-70 interchange and proceeded south through Aurora until final completion in early 1976 with the final link to I-25 opening to traffic. Route description I-225 is one of the three freeways that serves Aurora and is the only existing Interstate in Colorado that never runs concurrent with another highway in its entire length. The southern end of I-225 begins at an interchange with I-25, as a typical four-lane Interstate with a limit. The road heads northeastward through southern Denver, and, after having exits with DTC Boulevard and Yosemite Street in Greenwood Village, 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 eastside, the highway interchanges with SH 83 at the northern boundary of the park. Following the exit at SH 83, the freeway enters Aurora, where it turns northward, maintaining six throughlanes and auxiliary lanes at each exit, a 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 SH 30). After crossing Sand Creek, the freeway interchanges with Colfax Avenue (also signed as US 40, US 287, and I-70 Bus.), 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 I-70. The northbound ramp to