Thomas Jefferson stood here on October 25, 1783 and thus this rock formation was named. He was so struck by it that he wrote a passage in "Notes on the State of Virginia" describing it as "one of the most stupendous scenes in Nature." It's very popular in Harper's Ferry, nestled within the Appalachian Trail. The park is open every day from 9 AM to 5 PM. There is an entrance fee of $20 per regular vehicle; see the nps.gov website for more details.