Clarksville CaveClarksville Cave is a cave in Albany County, New York|Clarksville], Albany [County, New York|Albany County], New [York (state)|New York].Clarksville Cave is a horizontal cave system with of passage and three entrances.HistoryThe history of Clarksville Cave is one of the longest of any cave in New York. The earliest known petroglyph found in the cave is from 1811, and a letter describing the cave was written by Teunis Houghtaling in 1818.