Jefferson County, New York
Jefferson County is a county in the U.S. state of New York. As of the 2020 census, the population was 116,721. The county seat is Watertown. The county is named after Thomas Jefferson, third President of the United States of America. Jefferson County is west of Lake Ontario, and southeast from the Canada–US border. Jefferson County is mostly rural area. Fort Drum is inside Jefferson County. The 10th Mountain Division is inside Fort Drum. Jefferson County is part of New York's 21st congressional district.