Mountainside, New Jersey Demographics & Population 2026
During the 2020–2024 ACS period, Mountainside, New Jersey had a total population of 7,049, the 230th largest borough in New Jersey, with a median household income of $211,538, which is 104% higher than the state average. The poverty rate is 3.7%.
Data vintage: U.S. Census Bureau ACS 2020–2024 5-Year Estimates · refreshed July 2026 · Methodology & source notes
Key Takeaways
- Household income is 104% above the state average — one of the wealthiest communities in New Jersey.
- An exceptionally low poverty rate of 3.7% — among the lowest in New Jersey.
Mountainside Quick Facts
How Mountainside Changed
Change from the 2019–2023 ACS period to 2020–2024. These are rolling five-year estimates, not year-over-year measurements.
| Metric | 2019–2023 | 2020–2024 | Change |
|---|---|---|---|
| Population | 6,967 | 7,049 | +1.2% |
| Median household income | $210,100 | $211,538 | +0.7% |
| Median home value | $755,600 | $810,300 | +7.2% |
How Mountainside Compares
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Detailed income brackets
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
Moderate diversity with one or two groups making up the majority.
State average: 66 | National average: 61
Education
Educational Attainment (Adults 25+)
Mountainside Rankings in New Jersey
Explore New Jersey Rankings
Other Cities in Union County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| Elizabeth | 137,302 | $66,555 | 15.8% | $449,300 |
| Plainfield | 55,236 | $85,908 | 15.5% | $410,800 |
| Linden | 44,192 | $92,915 | 9.6% | $419,700 |
| Westfield | 31,111 | $232,629 | 1.8% | $953,400 |
| Rahway | 30,109 | $91,461 | 9.5% | $386,400 |
| Summit | 22,705 | $190,304 | 5.5% | $994,500 |
| Roselle | 22,646 | $92,762 | 9.5% | $379,900 |
| Roselle Park | 14,093 | $109,679 | 6.6% | $443,200 |
| New Providence | 13,727 | $161,599 | 2.1% | $769,900 |
| Kenilworth | 8,401 | $118,611 | 6.3% | $522,200 |
Cities Similar to Mountainside
These cities in the same state have comparable population and economic profiles.
| City | Population | Median Income | Home Value | Bachelor's+ | Poverty |
|---|---|---|---|---|---|
| North Caldwell | 6,656 | $208,245 | $904,500 | 80.5% | 1.7% |
| Lincroft | 6,939 | $189,000 | $807,300 | 65.2% | 2.0% |
| Bridgewater Center | 6,505 | $205,595 | $703,700 | 60.8% | 3.1% |
| Rumson | 7,241 | $250,000+ | $1,679,300 | 82.1% | 3.2% |
| Packanack Lake | 6,321 | $213,103 | $601,000 | 63.6% | 1.6% |
Population Overview
Mountainside is a small city located in New Jersey, within Union County. The total population is 7,049. It ranks as the 230th most populous out of 700 Census-designated places in New Jersey.
Age Demographics
The median age in Mountainside is 48.0 years. This is 20% higher than the state median of 40.1 years.
Economy, Income & Housing
The median household income in Mountainside is $211,538. This is 104% higher than the state median of $103,556. It is also 162% higher than the national median of $80,734. The poverty rate stands at 3.7%. This is 62% lower than the state poverty rate of 9.7%. This exceptionally low poverty rate indicates strong economic prosperity across the community. The unemployment rate is 3.5%. This is 45% lower than the state rate of 6.3%. The median home value is $810,300. Housing costs are 78% higher than the state median of $454,400. The home-value-to-income ratio is 3.8x. 87.9% of occupied housing units are owner-occupied. This homeownership rate is 38% higher than the state average of 63.8%.
Race & Ethnicity
The largest racial or ethnic group in Mountainside is White (non-Hispanic), making up 71.3% of the population. Hispanic or Latino residents account for 13.2%. The Black or African American population (2.2%) is well below the state average of 12.2%.
Education
67.3% of residents aged 25 and older hold a bachelor's degree or higher. This is 54% higher than the state rate of 43.6%. Nationally, 35.7% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 96.2%. Notably, 38.0% of adults hold a graduate or professional degree, indicating a highly educated workforce.
Data Sources & Methodology
All demographic data for Mountainside, New Jersey is sourced from the U.S. Census Bureau's American Community Survey (ACS) 2020–2024 5-Year Estimates. The ACS collects data from approximately 3.5 million households annually and pools five years of responses so that even small communities can be measured, though the margin of error widens as the population falls. Comparisons are made against New Jersey state averages and national averages calculated from the same dataset. Rankings reflect the city's position among all 700 Census-designated places in New Jersey. Read more about how these figures are produced on our methodology page, or visit data.census.gov for official data.
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Frequently Asked Questions
What is the population of Mountainside, New Jersey?
Mountainside, New Jersey has a population of 7,049 according to the most recent U.S. Census ACS 5-Year Estimates.
What is the median household income in Mountainside, NJ?
The median household income in Mountainside is $211,538, which is 162% higher than the national median of $80,734.
What is the poverty rate in Mountainside, NJ?
The poverty rate in Mountainside is 3.7%. This means approximately 259 residents live below the federal poverty line.
What is the racial makeup of Mountainside, New Jersey?
Mountainside's population is 71.3% White, 2.2% Black, 13.2% Hispanic/Latino, and 11.4% Asian.
What is the median home value in Mountainside, NJ?
The median home value in Mountainside is $810,300. The home-value-to-income ratio is 3.8x.
How educated is Mountainside, New Jersey?
67.3% of adults (25+) in Mountainside hold a bachelor's degree or higher, and 38.0% hold a graduate or professional degree.