Ulster County is a county in the U.S. state of New York. It is situated along the Hudson River. As of the 2020 census, the population was 181,851. The county seat is Kingston. The county is named after the Irish province of Ulster. The county is part of the Hudson Valley region of the state.

Kingston is the only city in, and the county seat of, Ulster County, New York, United States. It is 91 miles (146 km) north of New York City and 59 miles (95 km) south of Albany. The city's metropolitan area is grouped with the New York metropolitan area around Manhattan by the United States Census Bureau. The population was 24,069 at the 2020 United States Census.