Swamp White Oak
Mile 177.9 - Beside the bench, there's a plaque that reads:
This tree is the most outstanding Swamp White Oak specimen known in the State of Maryland. It is listed as a Maryland State record in the Maryland Big Tree Champion program. In 1991, the tree was 16 feet, 2 inches in circumference 4 feet above the ground. The tree was 82 feet high with a spread of 84 feet.
And if that doesn't impress you, you can always rest yourself on the bench.