St. Agnes Chapel was an Upper West Side Episcopal "plant chapel" of Trinity Church (New York City), one of many. It was located at 121-147 West 91st Street, between Amsterdam and Columbus Avenues. It was at first reused by its parish school and then demolished for a gymnasium in the 1940s. In 1934, Downtown Trinity Parish decided to close the small congregation, already split from nearby Episcopal churches. Eager to expand, the adjacent parish school, also named Trinity, bought it as a gymnasium space and demolished it for a more permanent structure in 1943.