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
Oklahoma State Highway 51 area. In Sand Springs, SH-51 crosses the Arkansas River with SH-97 before merging onto the Sand Springs Expressway (U.S. Highway 412/U.S. Highway 64). When this freeway ends at I-244 near downtown Tulsa, Highway 51 merges onto I-244 southbound only to exit one mile (1.6 km) later, where it overlaps US-64/US-75. This freeway is actually Interstate 444, but the interstate designation is not shown on signs. After one more mile, SH-51 leaves the interstate with US-64 and becomes the Broken Arrow Expressway, a freeway running northwest-southeast through Tulsa which is known as "The BA" by locals and local media. US-64 leaves