Mercer Island Demographic Information

Click here for a wide range of demographic information from the US Census Bureau.

2020 Census Statistics

2020 Census Total Island Population: 25,748
2020 Census Occupied Housing Units: 10,199
2020 Census Average Island Household Size: 2.50
2000 Census Median Household Income: $147,566
Population Change from 2010 to 2020: +3,049 (14.1%)

2010 Census Statistics

2010 Census Total Island Population: 22,699
2010 Census Island Population Over Age 18: 17,126
2010 Census Occupied Housing Units: 9,109
2010 Census Average Island Household Size: 2.48
2000 Census Median Household Income: $121,948
Population Change from 2000 to 2010: +663
Occupied Housing Unit Change from 2000 to 2010: +672

2000 Census Statistics

2000 Census Total Island Population: 22,036
2000 Census Island Population Over Age 18: 16,312
2000 Census Occupied Housing Units: 8,437
2000 Census Average Island Household Size: 2.58
2000 Census Median Household Income: $91,904
Population Change from 1990 to 2000: +1,220
Occupied Housing Unit Change from 1990 to 2000: +430

1990 Census Statistics

1990 Census Total Island Population: 20,816
1990 Census Island Population Over Age 18: 15,887
1990 Census Occupied Housing Units: 8,007
1990 Census Average Persons per Household: 2.59
1990 Census Median Household Income: $61,572

Annual Population Estimates (as Determined by Washington State)

2022: 25,780
2021: 25,790
2020: 25,748
2019: 24,470
2018: 24,270
2017: 24,210
2016: 23,660
2015: 23,480
2014: 23,310
2013: 22,720
2012: 22,690
2011: 22,710
2010: 22,890
2009: 22,720
2008: 22,650
2007: 22,380
2006: 21,860
2005: 21,710
2004: 21,830
2003: 21,840