Mercer Island, WA Profile: Facts & Data


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Mercer Island, Washington - Basic Facts

The City of Mercer Island had a population of 25,133 as of July 1, 2018. Mercer Island ranks in the upper quartile for Population Density when compared to the other cities, towns and Census Designated Places (CDPs) in Washington. See peer rankings below.

The primary coordinate point for Mercer Island is located at latitude 47.5627 and longitude -122.2257 in King County. The formal boundaries for the City of Mercer Island (see map below) encompass a land area of 6.32 sq. miles and a water area of 0 sq. miles. King County is in the Pacific time zone (GMT -8). The elevation is 335 feet.

The City of Mercer Island (GNIS ID: 2411082) has a C1 Census Class Code which indicates an active incorporated place that does not serve as a county subdivision equivalent. It also has a Functional Status Code of "A" which identifies an active government providing primary general-purpose functions.

Washington is one of 20 states where Census County Divisions (CCDs) are used for statistical tracking of subdivisions within each county. The City of Mercer Island is located within Seattle East Division of King County.

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  1. Mercer Island 2018 Demographic Data
  2. Growth Rates for Mercer Island (Historical & 5-Year Forecast)
  3. Peer Comparisons (Rank and Percentile)
  1. Neighborhoods Demographics (Home Values, Household Income, etc.)
  2. Washington Research Tools (Easy Tools & Current Data)
  3. Washington Data Comparison Tool - 2018 Demographics

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Boundary Maps, Demographic Data, School Zones Review maps and data for the neighborhood, city, county, ZIP Code, and school zone. July 1, 2018, data includes home values, household income, percentage of homes owned, rented or vacant, etc.


Mercer Island, WA Data & Demographics (As of July 1, 2018)


Total Population 25,133
Population in Households 25,133
Population in Familes 21,554
Population in Group Qrtrs 0
Population Density2 3,977
Diversity Index3 47


Median Household Income $150,964
Average Household Income $212,542
Per Capita Income $85,379


Total Housing Units 10,835 (100%)
Owner Occupied HU 6,910 (63.8%)
Renter Occupied HU 3,186 (29.4%)
Vacant Housing Units 739 ( 6.8%)
Median Home Value $1,166,809
Average Home Value $1,265,355


Total Households 10,096
Average Household Size 2.49
Family Households 7,222
Average Family Size 3
  1. Demographics are point estimates for July 1st of the current year and each for the forecast years. See References for more information.
  2. Population Density = Total Population per square mile.
  3. The Diversity Index is a scale of 0 to 100 that represents the likelihood that two persons, chosen at random from the same area, belong to different race or ethnic groups. If an area's entire population belongs to one race AND one ethnic group, then the area has zero diversity. An area's diversity index increases to 100 when the population is evenly divided into two or more race/ethnic groups.


2010-2018 2018-2023
Population 1.24% 1.22%
Households 1.25% 1.17%
Families 1.22% 1.17%
Median Household Income   1.15%
Per Capita Income   1.63%

Mercer Island, WA - Peer Comparisons by Rank and Percentile

The table below compares Mercer Island to the other 627 incorporated cities, towns and CDPs in Washington by rank and percentile using July 1, 2018 data. The location Ranked # 1 has the highest value. A location that ranks higher than 75% of its peers would be in the 75th percentile of the peer group.

Variable Description Rank Percentile
Total Population # 46 93rd
Population Density # 44 93rd
Diversity Index # 212 66th
Median Household Income # 9 99th
Per Capita Income # 5 99th

Additional comparisons and rankings can be made with a VERY EASY TO USE Washington Census Data Comparison Tool.

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Compare Washington July 1, 2018 Data
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