 Its architect was Ernest Flagg.It was designated a landmark by the New York City Landmarks Preservation Commission in 1973, and added to the National Register of Historic Places in 1977.Congregation Kehilath Jeshurun (originally "Anshe Jeshurun"), a Modern Orthodox synagogue founded by Russian Jewish immigrants in 1872, is located at 125 East 85th Street, between Park Avenue and Lexington Avenue, in a building built in 1902.