Near this valley, SR 140 enters the Sheldon National Wildlife Refuge, an area designed to provide habitat for pronghorn and conserve native fish, bird and plant species. The highway travels about  through the wildlife range towards the Oregon state line. SR 140 ends at the border in the northwest corner of Humboldt County, with Oregon Route 140 continuing northwest towards Adel and Lakeview.
SR 140 nears the Sheldon National Wildlife Refuge, an area designed to support pronghorn and protect native fish, bird, and plant species. The highway travels through this wildlife range before reaching the Oregon state line. SR 140 ends at the border in Humboldt County's northwest corner, with Oregon Route 140 continuing toward Adel and Lakeview.