The Borough of Clark, incorporated May 5, 1848, formerly Clarksville, is a rural residential lake side community with approximately 650 residents, located in Mercer County, Pennsylvania. In the early 60's the entire village of Clarksville was moved to allow the U.S. Army Corps of Engineers to build a dam to serve as flood control for the Shenango Valley. At that time a new village was laid out on property south of the old town. Many residents chose to move their homes to new lots on the hill while other homes continued to be built. Other houses that were not moved were used by the workers of the reservoir and eventually demolished. The Erie Canal Extension went along the Shenango River route and is now under water. Clarksville had quite a history with the Erie Canal coming through it. The old town is now covered by water, grass, trees and weeds. The only remains of it are some old asphalt streets that can be found amongst the trees along with the main road, which is visible when the water is lowered. There is now a marina where former businesses and residences used to be. In 1968, with new roads, power and telephone lines installed, the town's new identity of Clark was established.