Mountainside Flag

Mountainside

County:
Union County
County Seat:
No
Area (mi²):
3.996
State:
New Jersey

Mountainside is a borough located in Union County, New Jersey. Mountainside has a 2026 population of 7,346. Mountainside is currently growing at a rate of 0.81% annually and its population has increased by 5.06% since the most recent census, which recorded a population of 6,992 in 2020.

The median household income in Mountainside is $211,538 with a poverty rate of 3.73%. The median age in Mountainside is 48 years: 47.9 years for males, and 48.1 years for females. For every 100 females there are 98.1 males.

7.3K
Total Population
1,838
Density (mi²)
59 0.81%
Growth

Mountainside Population

Mountainside Population

Data after 2023 is projected based on recent change

Year ↓
Population
Growth
Annual Change
20267,346590.81%
20257,287590.82%
20247,2281892.69%
20237,039590.85%
20226,980-33-0.47%
20217,013-11-0.16%
20206,9921041.51%
20196,888220.32%
20186,866250.37%
20176,841170.25%
20166,824380.56%
20156,786100.15%
20146,776-6-0.09%
20136,782490.73%
20126,733210.31%
20116,712440.66%
20106,668-17-0.25%
20006,602-55-0.83%
19906,657-461-6.48%
19807,118-402-5.35%
19707,5201,19518.89%
19606,32500%

Median Age

Overall: 48 years
Female: 48.1 years
Male: 47.9 years

Mountainside Adults

There are 5,514 adults, (1,709 of whom are seniors) in Mountainside.

Sex Ratio

Female: 3,558 (50.5%)
Male: 3,491 (49.5%)

Demographics

The racial composition of Mountainside includes 73.97% White, 11.76% Asian, and smaller percentages for Black or African American, other race and multiracial populations.

Population by Race

Race
Population ↓
Percentage (of total)
White5,21473.97%
Asian82911.76%
Two or more races71310.11%
Black or African American1552.2%
Other race1381.96%
Race
Population ↓
Percentage (of total)
Two or more races5878.33%
White1852.62%
Other race1341.9%
Asian250.35%
Race
Population ↓
Percentage (of total)
White5,02971.34%
Asian80411.41%
Black or African American1552.2%
Two or more races1261.79%
Other race40.06%

Mountainside Marital Status

Economics and Income Statistics

Mountainside 's average per capita income is $89,602. Household income levels show a median of $211,538. The poverty rate stands at 3.73%.

Families: A family includes the owner or renter of the home along with everyone related to them - whether through birth, marriage, or adoption. This includes relatives like spouses, children, parents, siblings, grandparents, and any other family members.
Households: A household includes all the people who occupy a housing unit (such as a house or apartment) as their usual place of residence.
Non Families: A nonfamily household is either someone living alone or when the owner/renter lives with people they aren't related to, like roommates.
Name
Median ↓
Mean
Married Families$245,476-
Families$219,531$254,681
Households$211,538$237,360
Non Families$178,125$149,761

$89,602

Average Income

$211,538

Median Household Income

3.73%

Poverty Rate

Nearby Cities

Sources

  1. US Census State Population Estimates - Most recent state estimates from the Census Bureau's Population Estimates Program
  2. US Census County Population Estimates - Most recent county estimates from the Census Bureau's Population Estimates Program
  3. American Community Survey (2009 - 2013)
  4. Census QuickFacts
  5. Historical Populations of States and Counties (1790 - 1990)