The Choptank River is a major tributary of the Chesapeake Bay and the largest river on the Delmarva Peninsula. Running for 71 miles (114 km), it rises in Kent County, Delaware, runs through Caroline County, Maryland, and forms much of the border between Talbot County, Maryland, on the north, and Caroline County and Dorchester County on the east and south. It is located north of the Nanticoke River, and its mouth is located south of Eastern Bay. Cambridge, the county seat of Dorchester County, and Denton, the county seat of Caroline County, are located on its south shore.
Its watershed area in Maryland is 1,004 square miles (2,600 km2), of which 224 square miles (580 km2) is open water, so it is 22% water. The predominant land use is agricultural with 418 square miles (1,080 km2), or 48% of the land area. The river is named after the native Choptank people.
