Alexandria is a town in the Thousand Islands region of the U.S. state of New York, within Jefferson County. The town's population was 3,741 at the 2020 United States Census. The town is named after Alexander LeRay, the son of an early developer. The village of Alexandria Bay is within the town.

Jefferson County is a county on the northern border of the U.S. state of New York. As of the 2020 census, the population was 116,721. Its county seat is Watertown. The county is named after Thomas Jefferson, third President of the United States of America. It is adjacent to Lake Ontario, southeast from the Canada–US border of Ontario. The county is part of the North Country region of the state.