Sullivan County is a county located in the U.S. state of New York. As of the 2010 census, the population was 77,547. The county seat is Monticello. The county's name is in honor of Major General John Sullivan, who was a hero in the American Revolutionary War.
The county was the site of hundreds of Borscht Belt hotels and resorts, which had their heyday from the 1920s through the 1970s.
In 2010, the center of population of New York was located at the southern edge of Sullivan County.
When the colony that is now New York State established its first twelve counties in 1683, the present Sullivan County was part of Ulster County. In 1809, Sullivan County was split from Ulster County.
In the late 19th century, the Industrial Revolution and the advent of factories driven by water power along the streams and rivers led to an increase in population attracted to the jobs. Hamlets enlarged into towns. As industry restructured, many of those jobs left before the middle of the twentieth century. The economy changed again after that, shifting to a more tourist-based variety and benefiting from resorts established by European Jewish immigrants and their descendants in what became called the Borscht Belt of the 20th century. Resort hotels featured a wide variety of entertainers, some nationally known. At the beginning of this period, visitors traveled to the area by train, and later by automobile. The natural resources of the area also provided a setting for numerous summer camps frequented by the children of immigrants and their descendants.