Hillside is a census-designated place (CDP) in Ulster County, New York, United States.

It is located just south of the city of Kingston, and the Town of Ulster.

[2] According to the United States Census Bureau, the CDP has a total area of 0.8 square miles (2.1 km2), all land.

There were 344 housing units at an average density of 409.1 per square mile (158.0/km2).

None of the families and 0.5% of the population were living below the poverty line, including no under eighteens and 3.0% of those over 64.