High Quality Content by WIKIPEDIA articles! Interstate 225 (I-225) is a spur route of Interstate 25 in Colorado. It is the only auxiliary route of Interstate 25, and one of two in 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.