The former Hancock County Jail is located at 40 State Street in Ellsworth, the county seat of Hancock County, Maine. Built in 1885–86, it has a well-appointed living space for the jailer in the front, and a series of cells in the back. It was operated as a jail until the early 1970s, and is now home to the Ellsworth Historical Society, which operates it as a museum. It was listed on the National Register of Historic Places in 2008 for its architectural and historical significance.