Great Falls, Waterfall on the Housatonic River in Falls Village, Canaan, United States.

Great Falls is a series of waterfalls and rapids in the Potomac River near McLean, Virginia. The water plunges about 76 feet (23 meters) across a distance of less than one mile (1.6 kilometers) through steep rocky channels.

George Washington authorized the Patowmack Canal in the 18th century, which included five locks to help boats pass around the falls. This was an early effort to make the river navigable for commerce and transport.

Great Falls lies at Falls Village in the town of Canaan, in the Litchfield Hills; the village takes its name from the drop in the Housatonic. The falls are the highest-volume waterfall in Connecticut, yet for most of the year much of the water is diverted just upstream for hydroelectric generation, so the flow a visitor sees varies with the plant's operation.

Swimming and wading are not allowed in the park because of strong currents and dangerous water conditions. Stay on marked trails and watch your step, especially when rocks are wet or icy.

The rock formations here are around 750 million years old, made of metamorphosed rock types like schist and gneiss. These ancient stones reveal the deep geological story beneath the modern landscape.