Business Loop I-19 - Sahuarita and Tucson

The 20.24 mile route formerly traveled along Nogales Highway north from Exit 69 at the town of Sahuarita. This represented an extent of U.S. 89 not supplanted by the original construction of Interstate 19 south to the Mexico border. Northward into Tucson, Business Loop I-19 transitioned to 6th Avenue for the final 1.8 miles. The route ended at Exit 261 along Interstate 10, just east of the I-19 north end.

Business Loop I-19 was commissioned in place of U.S. 89 when that route was retracted to Flagstaff as approved by the American Association of State Highway and Transportation Officials (AASHTO) on June 15, 1992. Decommissioned in 2004, Nogales Highway is no longer numbered as any route.