Golden Valley County is a county located in the U.S. state of Montana. As of the 2020 census, the population was 823, making it the third-least populous county in Montana. Its county seat is Ryegate.

U.S. Highway 12 (US 12) is an east–west United States Numbered Highway in the state of Montana. It extends approximately 597.576 miles (961.705 km) from the Idaho state line east to the North Dakota state line, the greatest distance that US 12 traverses through any state.