Rittenhouse Square is a public park in Center City Philadelphia, Pennsylvania that is the center of the eponymous Rittenhouse neighborhood. The square is one of the five original open-space parks planned by William Penn and his surveyor Thomas Holme during the late 17th century. Together with Fitler Square, the Rittenhouse neighborhood and the square comprise the Rittenhouse–Fitler Historic District. Rittenhouse Square is maintained by the non-profit group The Friends of Rittenhouse Square.