State Route 225 (SR 225) is a state highway in Elko County, Nevada, United States. Known as the Mountain City Highway, it connects the city of Elko to the town of Owyhee near the southwestern Idaho border via Mountain City. The route provides connections to Mountain Home, Idaho and Interstate 84 via Idaho State Highway 51.

SR 225 previously existed as portions of several pre-1976 routes, including State Route 11, State Route 43 and State Route 51.

The entire route is in Elko County.