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
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