Williamstown is an unincorporated community in northern Lewis County, Missouri, United States. It is located at the intersection of Missouri Supplemental Routes A and E, approximately twenty miles northwest of Canton. The community is part of the Quincy, IL–MO Micropolitan Statistical Area.
- U.S. Geological Survey Geographic Names Information System: Williamstown, Missouri
- Steinbeck, Dan (Sep 28, 2006). "Williamstown, now 150 years old, was once a busier town". Press-News Journal. p. 4. Retrieved 1 November 2015.
- Eaton, David Wolfe (1916). How Missouri Counties, Towns and Streams Were Named. The State Historical Society of Missouri. pp. 185.
- "Lewis County Place Names, 1928–1945 (archived)". The State Historical Society of Missouri. Archived from the original on 24 June 2016. Retrieved 26 October 2016.