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.