Interstate 225 (I-225) is a 11.959 mile (19.246 km) 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 state highway 83, state highway 30 and Interstate 70 Business/U.S. Highway 40/U.S. Highway 287, known locally as Colfax Avenue. Construction on the freeway began in 1964 at the I-70 interchange and continued progressively through many years proceeding south through Aurora until final completion in 1976 with the final link between Yosemite Street and I-25.