Of 56 counties in the Treasure State, Custer County ranks 11th in terms of size (3,793 square miles). Custer County is in Southeast Montana. The total value of around 1,000 acres of riverfront property recently listed for sale in Custer County, Montana, was nearly $2 million. Browse all waterfront property for sale in Custer County on the Land Network to find the marina, lakefront and other recreational property that meets your needs, from waterside land perfect as a retirement investment to existing residential waterfront land and property for hunting, fishing and other outdoor-recreation pursuits! The most common type of land for sale by combined acreage in Custer County is undeveloped land.