About Us: The Mt. Vernon Branch Library (Walter C. McCanse Memorial Library) was the first to join with the Barry County Library in 1954 in a cooperative system. Population of the Lawrence County community is approximately 3,800. The town was named for George Washington`s home and serves as the county seat for Lawrence County. The Mt. Vernon Branch is located at 206 W. Water Street, just off of the court house square. The library serves Mt. Vernon and a large rural area as well as the Missouri Rehabilitation Center, Missouri Veterans Home, Missouri Baptist Children`s Home, and Missouri Division of Youth Services Treatment Center.