Basin is a town in, and the county seat of, Big Horn County, Wyoming, United States. The population was 1,239 at the 2000 census. The community is located near the center of the Bighorn Basin with the Big Horn River east of the town. Basin's post office, built in 1919, is listed on the National Register of Historic Places.
Basin is located at 44°22′44″N 108°2′35″W / 44.37889°N 108.04306°W / 44.37889; -108.04306 (44.378777, -108.043100).
According to the United States Census Bureau, the town has a total area of 2.0 square miles (5.3 km²), of which, 2.0 square miles (5.2 km²) of it is land and 0.04 square miles (0.1 km²) of it (1.47%) is water.