Terryville is a census-designated place in Litchfield County, Connecticut, United States, and is the largest village within the town of Plymouth. In the 2010 census, Terryville had a population of 5,387, out of 12,243 in the entire town of Plymouth. The village is named for Eli Terry Jr., the son of the well-known clockmaker Eli Terry Sr. Terryville is also home to the Lock Museum of America. There is a water wheel located in downtown Terryville that is dedicated to the son of Eli Terry Sr.