Hadlock Pond, also known as Lake Hadlock or Sunderland Pond, is a small man-made reservoir formed on a tributary of Halfway Creek in the town of Fort Ann in Washington County, New York, United States.Constructed in 1896, the original dam was of earthen construction, or rock fill. It had a height of 29 feet (8.8 m), with a width of 850 feet (260 m).