Lake Champlain

Lake Champlain is a natural freshwater lake that lies in a valley formed by the collision of tectonic plates and later carved by glacial activity during the Pleistocene. It is fed by numerous rivers and streams, including the Winooski, Lamoille, and Missisquoi rivers from Vermont, and the Ausable and Saranac rivers from New York. The lake drains northward via the Richelieu River into the Saint Lawrence River, making it part of the Saint Lawrence watershed. Its water level is regulated by the Moses-Saunders Dam on the Saint Lawrence, but the lake itself is not dammed. The lake's basin is home to several islands, including the largest, Isle La Motte, which is known for its fossil-rich limestone. The lake's shoreline is highly irregular, with many bays, points, and wetlands that support a diverse array of plant and animal life.

Human habitation around Lake Champlain dates back at least 10,000 years, with indigenous peoples such as the Abenaki and the Iroquois using the lake for transportation, fishing, and trade. The first European to see the lake was the French explorer Samuel de Champlain, who arrived in 1609 and named it after himself. The lake became a strategic military waterway during the French and Indian War and the American Revolutionary War, with notable battles such as the Battle of Valcour Island in 1776, where Benedict Arnold's small fleet delayed a British invasion. In the War of 1812, the Battle of Plattsburgh was fought on the lake, securing American control of the region. The lake also served as a major transportation route for timber, iron, and other goods in the 19th century, with the Champlain Canal connecting it to the Hudson River in 1823.

Lake Champlain supports a rich ecosystem, including over 80 species of fish, such as lake trout, landlocked Atlantic salmon, and walleye, as well as a variety of migratory birds and mammals. The lake is also home to the spiny softshell turtle, a threatened species in Vermont. However, the lake faces significant environmental challenges, particularly from nutrient pollution, primarily phosphorus from agricultural runoff and wastewater treatment plants. This has led to frequent harmful algal blooms, which can produce toxins harmful to humans and animals. Invasive species, such as the zebra mussel and the spiny water flea, have also disrupted the food web. Efforts to address these issues include the Lake Champlain Basin Program, which coordinates research and restoration projects, and the implementation of total maximum daily loads (TMDLs) for phosphorus.

Beyond its well-known features, Lake Champlain holds several lesser-known distinctions. The lake is home to the oldest known fossil reef in the world, located on Isle La Motte, dating back about 480 million years. The lake's name in the Abenaki language is "Bitawbagok," meaning "waters in between," reflecting its position between the Green Mountains and the Adirondacks. The lake is also the site of the only known naval battle fought entirely on freshwater in the American Revolution, the Battle of Valcour Island. Additionally, the lake's "Champ" legend has been a part of local folklore since the 19th century, with reported sightings and even a 1977 photograph that remains unverified. The lake also has a unique geological feature: it is part of the Champlain Sea, a temporary inlet of the Atlantic Ocean that existed after the last ice age, leaving behind marine fossils in the region.

Champlain Sea

A temporary saltwater body that covered the Lake Champlain and St. Lawrence River valleys after the last glacial retreat, about 13,000 to 10,000 years ago.

TMDL

Total Maximum Daily Load, a regulatory term in the U.S. Clean Water Act that sets the maximum amount of a pollutant a water body can receive while still meeting water quality standards.

Spiny softshell turtle

A freshwater turtle species (Apalone spinifera) found in Lake Champlain, listed as threatened in Vermont.