Withamsville is a census-designated place (CDP) in Pierce and Union townships of Clermont County, Ohio, United States.

[5] Withamsville is located in western Clermont County along the southern border of Union Township.

Ohio State Route 125 runs through the center of the community, leading southeast 12 miles (19 km) to Bethel and northwest (via U.S. Route 50) 16 miles (26 km) to downtown Cincinnati.

Interstate 275 forms the northwest border of Withamsville, with access from Exit 65 where it crosses Route 125.

According to the United States Census Bureau, the CDP has a total area of 3.1 square miles (8.1 km2), all land.