The former route through Flagstaff is officially named "Historic Route 66". At Milton Road, US 66/US 89 intersected with SR 79 at its northern terminus. By 1941, SR 79 had been redesignated as US 89 Alternate (US 89A). US 89A, as its designation suggests, was an alternative, more direct route for US 89 traffic. US 89A provided a shorter travel distance between Flagstaff and Prescott, via Sedona and the mining town of Jerome. Today, US 89A is known as SR 89A. US 66/US 89 continued north on I-40 Business from the junction with US 89A to underpass with the Santa Fe Railway. On the other side of the underpass, the highway curved right onto Santa Fe Avenue and passed through downtown Flagstaff, including the Santa Fe Railway Depot. Just west of the depot is where current US 180 joins I-40 Business, former US 66 and former US 89.