U.S. Route 85 (US 85) is a part of the U.S. Highway System that travels from the Mexican border in El Paso, Texas, north to the Canadian border in Fortuna, North Dakota.

US 85 enters North Dakota in the southwest part of the state.

After running concurrently with North Dakota Highway 200 (ND 200), it eventually passes through part of the scenic Badlands, crosses the Little Missouri River and passes near the Theodore Roosevelt National Park (North Unit).

Then, at Watford City it travels west for 16 miles (26 km) where it turns back north before Alexander.

The stretch from Watford City to Williston is in the process of being converted into an undivided four-lane highway, and it should be substantially completed in 2014.