[15] The Mohegan were a tribe of Native Americans once associated with the Pequot of easternmost Connecticut, who were pushed successively west to the area of the Housatonic River during the 17th and into the 18th century.

There is no indication of them ever inhabiting northern Westchester County in the vicinity of Peekskill, or any other nearby area.

The change in syntax, reversing the modern community's name to "Mohegan Lake", dates back to the early 1970s, before which residents commonly referred to it as "Lake Mohegan", the name still used by the United States Census Bureau for the CDP.

18.9% of all households were made up of individuals, and 4.7% had someone residing alone who was 65 years of age or older.

St. George's Church, built in 1911-12 and designed by Hewett & Bottomley in the Romanesque Revival style, was added to the National Register of Historic Places on May 8, 2012.

[20] St. Mary Church has a marker commemorating cadets of the Mohegan Lake School, a military academy for boys from 1880 to 1934.