The National Park Service now protects the historic battlefield of 1781. Much of the land is as it looked at that time with the exception of the paved roads that criss-cross the park. During the siege, many of the trees that filled areas of the field had been removed so that open lines of sight could be maintained. The earthworks are mostly recreated. The original earthworks were made by stacking large wicker cyclinders called "gabions" made from wild vines and thin tree branches growing in the woods. This same technique was used during the Civil War, one of which is shown below of earthworks built at Yorktown during the 1862 siege.
The layout of the park and the reconstruction of the earthworks is based on precise military maps that were created at the time. The difference today is that the earthworks were not created in the same way as those built during the 1781 siege. They have a rounded shape to them and the artillery pieces are placed in positions that most likely never occured. The field cannon sitting on top of an embankment like the image below, while highly photogenic, would have subjected the firing crew to a fusillade of enemy fire. Instead, the artillery piece would have been placed in the depression and fired over the earthen wall. Gun powder and shells would also be located within the depression and should enemy fire strike the position, the resulting explosion would protect the adjoining gun positions.
Prior to inclusion in the National Park system, Yorktown Battlefield was part of the Yorktown Country Club. The battlefield was part of its 18-hole Riverview Golf Course. Intent upon preserving the battlefield, the owner of the golf course designed it around existing earthworks.