Mercer Island Flag

Mercer Island

County:
King County
County Seat:
No
Area (mi²):
6.383
State:
Washington

Mercer Island is a city located in King County, Washington. Mercer Island has a 2026 population of 25,078. Mercer Island is currently declining at a rate of -0.44% annually and its population has decreased by -2.61% since the most recent census, which recorded a population of 25,750 in 2020.

The median household income in Mercer Island is $219,069 with a poverty rate of 3.81%. The median age in Mercer Island is 46.4 years: 45.7 years for males, and 46.9 years for females. For every 100 females there are 91.0 males.

25.1K
Total Population
3,929
Density (mi²)
-112 -0.44%
Growth

Mercer Island Population

Mercer Island Population

Data after 2023 is projected based on recent change

Year ↓
Population
Growth
Annual Change
202625,078-112-0.44%
202525,190-112-0.44%
202425,3022380.95%
202325,064-41-0.16%
202225,105-232-0.92%
202125,337-417-1.62%
202025,750-127-0.49%
201925,877-29-0.11%
201825,9061500.58%
201725,7561330.52%
201625,6232400.95%
201525,3836272.53%
201424,7563111.27%
201324,4453841.6%
201224,0615162.19%
201123,5457753.4%
201022,770710.31%
200022,0361,2205.86%
199020,816-706-3.28%
198021,5222,47512.99%
197019,0477,04758.73%
196012,00000%

Median Age

Overall: 46.4 years
Female: 46.9 years
Male: 45.7 years

Mercer Island Adults

There are 19,873 adults, (5,610 of whom are seniors) in Mercer Island.

Sex Ratio

Female: 13,251 (52.4%)
Male: 12,056 (47.6%)

Demographics

The racial composition of Mercer Island includes 63.56% White, 24.52% Asian, and smaller percentages for Black or African American, other race, Native American and multiracial populations.

Population by Race

Race
Population ↓
Percentage (of total)
White16,08563.56%
Asian6,20524.52%
Two or more races2,56010.12%
Black or African American2340.92%
Other race2170.86%
Native American60.02%
Race
Population ↓
Percentage (of total)
Two or more races4421.75%
White640.25%
Other race550.22%
Asian300.12%
Black or African American180.07%
Native American60.02%
Race
Population ↓
Percentage (of total)
White16,02163.31%
Asian6,17524.4%
Two or more races2,1188.37%
Black or African American2160.85%
Other race1620.64%

Mercer Island Marital Status

Economics and Income Statistics

Mercer Island 's average per capita income is $130,625. Household income levels show a median of $219,069. The poverty rate stands at 3.81%.

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
Families$250,001$393,619
Married Families$250,001-
Households$219,069$318,528
Non Families$85,246$141,965

$130,625

Average Income

$219,069

Median Household Income

3.81%

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)