Big Sandy is a town in Chouteau County, Montana, United States. The population was 598 at the 2010 census. Big Sandy, Montana, is where the Big Bud 747, the largest farm tractor in the world, was located from 1997 until 2009. The Lewis and Clark Trail, following U.S. Route 87, goes through Big Sandy and in 2011 the town was named in a list of "Most Livable Small Towns" by Montana Outdoors magazine.