South Windsor is a town in Hartford County, Connecticut, United States. The population was 25,420 at the 2010 census.
In 1659, Thomas Burnham (1617–1688) purchased the tract of land now covered by the towns of South Windsor and East Hartford from Tantinomo, chief sachem of the Podunk Indians. Burnham lived on the land and later willed it to his nine children. Beginning in the middle of the 17th century, a few of the settlers of Windsor began using land on the east bank of the Connecticut River for grazing and farming purposes. By 1700, a number of families had made their homes in this area, now known as South Windsor. In 1768, the residents of the area were allowed to incorporate as the separate town of East Windsor, though the area was informally referred to as East Windsor before this time, which then included all of East Windsor, South Windsor and Ellington. Known for its agriculture and ship building, the town supplied more than 200 volunteers during the American Revolution. In 1786, Ellington became an independent town. South Windsor itself was incorporated as a town in 1845. Tobacco was a major crop grown in South Windsor since its founding.