Ball's Bluff is a 600 yard long shale and sandstone cliff. It rises up a shallow bell curve from two ravines approximately 300 yards north and south of where you are standing. At this point, it is about 100 feet high, though just to the north (left) of this spot, it reaches its highest elevation of 110 feet above the river.
Note that the Potomac flows due south here. Thus, as you look across the river into Maryland, you are not looking northward as you might expect, but to the east.
Directly below you, more or less visible depending on the foliage, are the river and the floodplain on which Union troops landed on the morning of October 21, 1861. The landing point was upriver to your left some 300 yards. The Federals worked their way down the floodplain to the path at the southern end of the bluff which winds its way upward and comes out near the cemetery.
The Virginia channel of the river below you is, at normal water, some 75-80 yards wide. Beyond that channel is Harrison's Island which was picketed by Federal troops before the battle, and was the refuge sought by those same troops following the route at the end of the day. The island is two miles long and perhaps a quarter-mile wide.
Beyond it is the roughly 350 yard wide Maryland channel of the river on the other side of which, where you see several farm buildings, is Maryland proper. Follow the horizon to the right and you will see a water tower that marks the site of Poolesville, the small town that was General Stone's division headquarters from August, 1861, until his arrest in February, 1862. His approximately 10,000 troops were camped at various locations some 8-10 miles north and south of Poolesville so as to cover the river and watch for any Confederate activity.