Population by age, mapped by county
Median Age, 2018
In 2010, the median age of persons living in Washington state was 37.3 years. In 2018 the median age had increased to 38.3 years.
Jefferson County had the highest median age in 2010 at 53.9 years. By 2018, the median age in Jefferson County had reached 58.4 years.
In 2010, Whitman County, home of Washington State University, had the state's lowest median age at 24.4 years. In 2018, Whitman County still had the lowest median age at 24.3 years. Adams County was the only other county in Washington state with a median age less than 30 years in both 2010 (29.0 years and in 2017 (26.4 years).
Percent of Population Age 65 and Above, 2018
The age 65 and older population generally represents those nearing retirement.
In 2010, 12.3 percent of Washington State residents were 65 or older. In 2018, 15.8 percent Washington state residents were 65 and older.
Jefferson County had the highest share of the population age 65 and older in Washington state with 26.3 percent in 2010 and 36.8 percent in 2018.
Franklin County had the lowest share of population 65 and older, with only 7.3 percent in 2010 and 9.6 percent in 2018. Whitman County has the second lowest percentage of population 65 and older, with 9.5 percent in 2010 and 10.0 percent in 2018.
Percent of Population Age 85 and Above, 2018
In 2010, 1.7 percent of Washington state residents were age 85 or older. In 2018, 1.8 percent of Washington state residents were age 85 or above.
In 2010 and 2018, Garfield County's share of population age 85 or older was the highest of all counties in Washington with 4.2 percent and 4.4 percent respectively.
Franklin County had the lowest share of population 85 and in 2010 with 0.8 percent.
Adam County had the lowest share of population 85 and older in 2018 with 0.9 percent.
Last modified: September 10, 2019