Idaho State Highway 51


State Highway 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 Business Loop 84 intersection with American Legion Boulevard, and is not otherwise officially concurrent/overlaid with BL-84 or the former section of US-20 that follows American Legion Boulevard to Interstate 84/U.S. Route 20 east at Exit 95. As of February 2015, some map products such as Google Maps still show SH-51's former overlay with American Legion Boulevard.

Route description

SH-51's northern 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 Elko County, SR 225 connects with Interstate 80 in Elko.

History

The basic route of today's SH-51 was in place as early as the 1930s, mostly as an all-weather gravel road from Mountain Home until it reached the northern boundary of the Duck Valley Indian Reservation, and as an unimproved road on through to the Nevada border and then-NV Route 11 as of the 1937 map.

Major intersections

Elevation

on the highway ranges from a low of 2461 feet above sea level at the Snake River crossing,
to a high of 5400 feet at the Nevada border.
LocationMilepostElevationGNIS Feature ID
Mountain Home923146' - 959 m374044
C.J. Strike Reservoir
76.982461' - 750 m398659
Bruneau71.492549' - 777 m396181
Grasmere32.505089' - 1551 m376052
Riddle13.495367' - 1636 m398043
Miller Creek Settlement6.05325' - 1623 m396897
Owyhee, Nevada5400' - 1646 m842663