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
Indiana State Road 51 SR 51 went from SR 2 in Elkhart to the Michigan state line, now the route is State Road 19. In 1926, SR 51 was removed from that section of roadway and it was signed as US 112. There were plans to build SR 51 from State Road 10 to State Road 2, but that route was never built. Indiana State Road 51 State Road 51 in the U.S. state of Indiana is a north–south route on the state highway system in northwest Indiana. It consists of a route long from a point on U.S. Route 30 (Lincoln Highway) east