Ballston Spa is a village and the county seat of Saratoga County, New York, United States, located southwest of Saratoga Springs. The population of the village, named after Rev. Eliphalet Ball, a Congregationalist clergyman and an early settler, was 5,409 at the 2010 census. Ballston Spa lies on the border of two towns, situated partly in the Town of Ballston and partly in the Town of Milton.
The village was first settled in 1771. In 1787 Benajah Douglas, grandfather of 1860 presidential candidate Stephen A. Douglas, built the first tavern and hotel at Ballston Spa. It was located near the natural spring.
In 1803 Ballston Spa's Sans Souci Hotel, at the time the largest hotel in the United States, was built by Nicholas Low. Presidents, senators and governors stayed there, as well as many wealthy private citizens. Ballston Spa was incorporated as a village in 1807.
At one time the village was served by four railroads: the Delaware and Hudson Railway, the Ballston Terminal Railroad, the Schenectady Railway Company, and the Hudson Valley Railway.
The village was famous for its mineral water spring used for healing in sanatoriums, including the Hawthorne and Lithia springs.