The Old County Courthouse is an historic court house on Leyden Street and Market Street in the Town Square of Plymouth, Massachusetts. Built in 1749, the two-story wood-frame building is believed to be the oldest wooden courthouse in the United States; it stands on the site of the first courthouse built by Plymouth Colony settlers, and may incorporate elements of a 1670 building. The site was originally the site of Edward Winslow's first house in Plymouth.