East 143rd Street is also called St. Mary’s Street, a name shared with St. Mary’s Park.
Sources differ on where the park’s name comes from. NYC Parks says it was named for a Protestant Episcopal church that stood three blocks to the west until 1959; Wikipedia says park and church took their name from Mary, daughter of Adrian Janes, the iron founder who bought the land in 1857. The city purchased the park land in 1888–90.