Rittenhouse Square is one of the five original open-space parks planned by William Penn and his surveyor Thomas Holme during the late 17th century in central Philadelphia. The park is widely considered one of the finest urban public spaces in the United States.
The square cuts off 19th Street at Walnut Street and also at a half block above Manning Street. Its boundaries are 18th Street to the East, Walnut St. to the north, Rittenhouse Square West (a north-south boundary street), and Rittenhouse Square South (an east-west boundary street), making the park approximately two short blocks on each side.
Originally called Southwest Square, Rittenhouse Square was renamed in 1825 after David Rittenhouse, a descendant of the first paper-maker in Philadelphia, the German immigrant William Rittenhouse. William Rittenhouse’s original paper-mill site is known as Rittenhouse town, located in the rural setting of Fairmount Park along Paper Mill Run. David Rittenhouse was a clockmaker and friend of the American Revolution, as well as a noted astronomer; a lunar crater is named after him.