| District Name | Mountainside Borough School District |
| State | New Jersey |
| County | Union County |
| Statistical Area | New York-Newark-Jersey City, NY-NJ-PA |
| Cities/Towns | Mountainside |
| Total Students (2021) | 717 |
| District Growth Rate (2017-21) | 0.1% |
| Majority Race/Ethnicty | White (68.9%) |
| Free/Reduced Lunch Program | 1.12% |