Idaho State Highway 51 February 2015, some map products such as Google Maps still show SH-51's former overlay with American Legion Blvd. SH-51's northern terminus is in the city of Mountain Home in Elmore County. After turning south from Airbase Rd. and the intersection with SH-67, the road crosses the Snake River into Owyhee County and passes through the towns of Bruneau, Grasmere, and Riddle. About from the state border it enters the Duck Valley Indian Reservation. As the road crosses into Nevada it becomes State Route 225. The reservation's only major town, Owyhee is about south of the state border. After another through
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