Brandywine Battlefield Historic Site is a historical park that was operated by the Pennsylvania Historical and Museum Commission, on , near Chadds Ford, Delaware County, Pennsylvania in the United States. It is part of the site of the Battle of Brandywine fought on September 11, 1777, during the American Revolution. The battle was a major victory for the British and enabled them to capture the city of Philadelphia. Brandywine Battlefield Park became a Pennsylvania State Park in 1949 and a National Historic Landmark in 1961.