Heathsville is a census-designated place in and the county seat of Northumberland County, Virginia, United States. Heathsville is in the easternmost county of the Northern Neck of Virginia, which was the birthplace of three of the first five Presidents of the United States- George Washington, James Madison, and James Monroe. It is the county seat of Northumberland County, and has housed four county courthouses since the first was built in 1663.