St. Thomas' Episcopal Church Complex is a historic Episcopalchurch complex at 158-168 W. Boston Post Road in Mamaroneck, Westchester County, New York. The complex, built between 1884 and 1925, comprises a cluster of four buildings. The Gothic Revival-style church is constructed entirely of rough-dressed Belleville brownstone with a red slate gable roof. It features a square tower on the north facade with clock faces and louvres. The property also includes the Parish House / Chapel (1884-1886), Endowment Building (1887), and Heathcote Hall (1925).[2]