St. Mary is an unincorporated community on the western border of the Blackfeet Native American Reservation adjacent to Glacier National Park. The village is the eastern terminus of the Going-to-the-Sun Road which bisects the park east to west, a distance of 53 miles (85 km). Fewer than 50 people reside in the village year-round; however, the population increases tenfold on a busy summer evening. It has several lodges, restaurants and cafés, a small grocery store, two gas stations and campgrounds. A large housing area for National Park Service personnel is located adjacent to the village, but within the park. U.S. Route 89 passes through the village, which lies between Saint Mary Lake in Glacier National Park and Lower St. Mary Lake on the Blackfeet Native American Reservation.