The Pelham Islands are a group of islands in western Long Island Sound that belonged to Thomas Pell in the 17th century. The islands, and most of the surrounding area, were purchased from the Siwanoy Indians by Pell in 1654, creating Pelham Manor. This large tract of land would eventually become the present-day Town and Village of Pelham and Pelham Manor, Town of Eastchester, cities of New Rochelle and Mount Vernon in Westchester County, and the Pelham Bay and Eastchester neighborhoods of the Bronx in New York City. Several of the Pelham Islands became part of New Rochelle after Jacob Leisler’s purchase of 6,000 acres from the Pell family in 1688. The remaining islands became part of Bronx County in 1895 with the establishment of the current Westchester-Bronx County line.

Islands