Idaho State Highway 51 Idaho State Highway 51 State Highway 51 (SH-51) is a state highway in southwestern Idaho from Mountain Home south to the Nevada border, where it continues as State Route 225 to Elko. It is the major north–south road in Owyhee County. As currently configured in the state's official milepoint log, SH-51 terminates at the BL-84 intersection with American Legion Blvd., and is not otherwise officially concurrent/overlaid with BL-84 (where the signs at I-84's Exits 90 and 99 say "To SH-51/To SH-67") or the former section of US-20 that follows American Legion Blvd. to I-84/US-20 east at Exit 95. As of
Utah State Route 51 Utah State Route 51 State Route 51 is a short highway completely within Utah County in northern Utah that connects SR-147 to US-89. The highway runs for three miles (5 km) and is an old routing of U.S. Route 91. The route begins at the intersection of 400 North (SR-147) and Childs Road in Spanish Fork, SR-51 heading northeast as a two-lane undivided highway on the latter. As the road exits Spanish Fork, it heads into a rural portion of Utah County. The continues northeast until 1600 North south of Springville, where the road turns north. The road continues north