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
Wyoming Highway 51 Interstate 90 which carries US 14/US 16. WYO 51 comes to an end at just under 25 miles at US 14/US 16/I-90 BUS. WYO 51 is signed as a secondary state highway, but not marked from the Interstate 90 interchanges like most secondary state highway frontage roads. Wyoming Highway 51 is the original alignment of US Route 14 and US Route 16. With the construction of Interstate 90, US 14 and US 16 were realigned onto that highway. Wyoming Highway 51 Wyoming Highway 51 is a long east-west Wyoming state highway located in Campbell and Crook Counties, between Gillette and