Basin is an unincorporated community and census-designated place (CDP) in Jefferson County, Montana, United States. It lies approximately 10 miles (16 km) southeast of the Continental Divide in a high narrow canyon along Interstate 15 about halfway between Butte and Helena. Basin Creek flows roughly north to south through Basin and enters the Boulder River on the settlement's south side. The population was 212 at the 2010 census,[2] down from 255 at the 2000 census.
Archaeologists have discovered evidence of human habitation from 10,000 years ago at a site near Clancy, 20 miles (32 km) northeast of Basin. From about 2000 BCE through the mid-19th century, nomadic tribes hunted bison in the grassy valleys that trend east, away from the Rocky Mountains and into the plains. By the time miners found gold in the streams in and near Basin, most of these tribes of Indians had been forced onto reservations by the U.S. government.