Adams County, Pennsylvania What is a watershed? A watershed is the land over which water flows before it drains into a water body such as a lake, stream, pond, wetland or ocean. No matter where you are, you are in a watershed! Adams County is divided into two major watersheds that flow into the Chesapeake Bay: the Susquehanna River Watershed and the Potomac River Watershed. The Conewago Creek is the largest stream in Adams County that drains to the Susquehanna River. Tributaries to the Conewago Creek include the South Branch Conewago, Bermudian, Latimore, Opposum, Beaverdam and Beaver creeks. Adams County has several tributaries that drain to the Potomac River via the Monocacy River. These tributaries include Marsh, Rock, Alloway, Middle, Piney and Tom's creeks. Adams County has over 1300 miles of streams. Virtually every stream that flows in Adams County originates within the county. We are the headwaters for the Chesapeake Bay. The Water Starts Here! According to the U.S. Census Bureau, the county has a total area of 522 square miles. 520 mi² of it is land and 2 mi² of it is water. The total area is 0.29% water. As of the 2000 Census, there are 91,292 people, 33,652 households, and 24,767 families residing in the county. At the time of the 2000 Census, Adams was the 4th fastest growing county in Pennsylvania. According to US Census Bureau 2003 population estimates, Adams County the 3rd fastest growing county in PA. Adams County receives on average 42.4 inches of rain a year.