Alpine Northwest is located on U.S. Route 26 (US 26) just north of Alpine, Wyoming, on the east shore of Palisades Reservoir.
According to the United States Census Bureau, the CDP has a total area of 1.5 square miles (3.8 km²), of which, 1.4 square miles (3.7 km²) of it is land and 0.69% is water.