Lake Mohegan is a census-designated place (CDP) located in the town of Yorktown and partially in the Town of Cortlandt, both in Westchester County, New York, United States. The population was 6,010 at the 2010 census. Locally, the area is known as Mohegan Lake, and the term "Lake Mohegan" is rarely used. However, this change dates back only to the early 1970s. Before then, local residents commonly referred to it as "Lake Mohegan". St. George's Church was listed on the National Register of Historic Places in 2012.According to the United States Census Bureau, the CDP has a total area of 3.1 square miles (8.0 km2), of which 2.9 square miles (7.5 km2) is land and 0.2 square miles (0.52 km2), or 5.52%, is water.