Washington Square, originally designated in 1682 as Southeast Square, is a 6.4 acres (2.6 ha) open-space park in Center City Philadelphia’s southeast quadrant and one of the five original planned squares laid out on the city grid by William Penn’s surveyor, Thomas Holme. It is part of both the Washington Square West and Society Hill neighborhoods. In 2005, the National Park Service took over ownership and management of Washington Square, through an easement from the City of Philadelphia. It is now part of Independence National Historical Park.
Initially, the square contained monuments to those who had fought in the American Civil War. One such monument was the Washington Grays Monument. In 1954, the decision was made to remove the civil war commemorations and focus the square solely on the memory of the Revolutionary War.
A sycamore moon tree in the square, planted in 1975, was grown from seeds that had been carried to the moon by astronaut Stuart Roosa on the Apollo 14 mission.