According to the United States Census Bureau, the town has a total area of 26.8 square miles (69.5 km2), of which 26.3 square miles (68.0 km2) is land and 0.58 square miles (1.5 km2), or 2.11%, is water.
By virtue of its location on the Connecticut River, Windsor functioned as a vital port. Merchants on both sides of the river shipped timber products, brick, livestock, wheat, tobacco and other produce to supply plantations in the West Indies, importing sugar, molasses, salt, and British manufactured textiles, ceramics, hardware and glass on return trips. Windsor’s Hooker and Chaffee mercantile firm maintained a store and packing houses right off Windsor’s Palisado Green. Small scale shipbuilding took place at the mouth of the Scantic River in what is now South Windsor, Warehouse Point in what is now East Windsor, and along the Farmington from as far upriver as today’s village of Poquonock (Stiles p. 428-9).