
Hillside township
- County:
- Union County
- County Seat:
- No
- Area (mi²):
- 2.767
- State:
- New Jersey
Hillside township is located in Union County, New Jersey. Hillside township has a 2025 population of 21,939. Hillside township is currently declining at a rate of -0.12% annually and its population has decreased by -1.81% since the most recent census, which recorded a population of 22,344 in 2020.
The average household income in Hillside township is $116,588 with a poverty rate of 9.63%. The median age in Hillside township is 36.3 years: 34.8 years for males, and 38 years for females.