Mountainside borough, New Jersey Demographics & Population 2026
As of 2026, Mountainside borough, New Jersey has a total population of 6,967, the 230th largest city in New Jersey, with a median household income of $210,100, which is 108% higher than the state average. The poverty rate is 2.9%.
Key Takeaways
- Household income is 108% above the state average — one of the wealthiest communities in New Jersey.
- An exceptionally low poverty rate of 2.9% — among the lowest in New Jersey.
- Near full employment with an unemployment rate of just 2.1%.
Mountainside borough Quick Facts
How Mountainside borough Compares
Median Household Income
Median Home Value
Economy & Housing
Household Income Distribution
Employment
Housing Overview
People & Demographics
Age Distribution
Race & Ethnicity
Diversity Index
Moderate diversity with one or two groups making up the majority.
State average: 65 | National average: 60
Education
Educational Attainment (Adults 25+)
Mountainside borough Rankings in New Jersey
Explore New Jersey Rankings
Other Cities in Union County
| City | Population | Median Income | Poverty | Home Value |
|---|---|---|---|---|
| Elizabeth city | 135,887 | $63,874 | 15.3% | $393,500 |
| Plainfield city | 54,515 | $80,334 | 17.1% | $383,300 |
| Linden city | 43,614 | $91,036 | 9.0% | $387,200 |
| Westfield town | 30,760 | $212,700 | 2.1% | $930,500 |
| Rahway city | 29,748 | $90,852 | 6.8% | $362,300 |
| Summit city | 22,512 | $199,107 | 3.9% | $969,900 |
| Roselle borough | 22,455 | $82,967 | 10.4% | $336,500 |
| Roselle Park borough | 13,965 | $104,418 | 5.1% | $405,800 |
| New Providence borough | 13,577 | $162,877 | 2.1% | $734,300 |
| Kenilworth borough | 8,339 | $126,295 | 6.0% | $521,100 |
Cities Similar to Mountainside borough
These cities in the same state have comparable population and economic profiles.
| City | Population | Median Income | Home Value | Bachelor's+ | Poverty |
|---|---|---|---|---|---|
| Belle Mead CDP | 6,772 | $219,215 | $777,600 | 73.0% | 2.7% |
| North Caldwell borough | 6,622 | $203,140 | $906,100 | 77.0% | 1.8% |
| Lincroft CDP | 6,901 | $168,945 | $719,000 | 62.4% | 2.2% |
| Rumson borough | 7,265 | $250,001 | $1,609,400 | 77.7% | 3.2% |
| Woodcliff Lake borough | 6,097 | $211,233 | $901,800 | 77.4% | 2.1% |
Population Overview
Mountainside borough is a small city located in New Jersey, within Union County. The total population is 6,967. It ranks as the 230th most populous out of 700 cities and towns in New Jersey.
Age Demographics
The median age in Mountainside borough is 48.7 years. This is 21% higher than the state median of 40.1 years.
Economy, Income & Housing
The median household income in Mountainside borough is $210,100. This is 108% higher than the state median of $101,050. Compared to the national median of $78,538, household income here is 168% higher. The poverty rate stands at 2.9%. This is 71% lower than the state poverty rate of 9.8%. This exceptionally low poverty rate indicates strong economic prosperity across the community. The unemployment rate is 2.1%. This is 66% lower than the state rate of 6.2%. The median home value is $755,600. Housing costs are 77% higher than the state median of $427,600. The home-value-to-income ratio is 3.6x. 86.9% of occupied housing units are owner-occupied. This homeownership rate is 36% higher than the state average of 63.7%.
Race & Ethnicity
The largest racial or ethnic group in Mountainside borough is White (non-Hispanic), making up 72.7% of the population. Hispanic or Latino residents account for 13.6%. The Black or African American population (1.1%) is well below the state average of 12.3%.
Education
66.2% of residents aged 25 and older hold a bachelor's degree or higher. This is 54% higher than the state rate of 42.9%. Nationally, 35.0% of adults hold at least a bachelor's degree. The high school graduation rate (or equivalent) is 96.5%. Notably, 36.9% of adults hold a graduate or professional degree, indicating a highly educated workforce.
Data Sources & Methodology
All demographic data for Mountainside borough, New Jersey is sourced from the U.S. Census Bureau's American Community Survey (ACS) 5-Year Estimates (2019-2023). The ACS collects data from approximately 3.5 million households annually, providing reliable estimates for communities of all sizes. 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. For official data, visit data.census.gov.
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Frequently Asked Questions
What is the population of Mountainside borough, New Jersey?
Mountainside borough, New Jersey has a population of 6,967 according to the most recent U.S. Census ACS 5-Year Estimates.
What is the median household income in Mountainside borough, NJ?
The median household income in Mountainside borough is $210,100, which is 168% higher the national median of $78,538.
What is the poverty rate in Mountainside borough, NJ?
The poverty rate in Mountainside borough is 2.9%. This means approximately 195 residents live below the federal poverty line.
What is the racial makeup of Mountainside borough, New Jersey?
Mountainside borough's population is 72.7% White, 1.1% Black, 13.6% Hispanic/Latino, and 11.4% Asian.
What is the median home value in Mountainside borough, NJ?
The median home value in Mountainside borough is $755,600. The home-value-to-income ratio is 3.6x.
How educated is Mountainside borough, New Jersey?
66.2% of adults (25+) in Mountainside borough hold a bachelor's degree or higher, and 36.9% hold a graduate or professional degree.