Other pages about the topic: Age data
Median Age, 2019

In 2010, the median age of persons living in Washington state was 37.3 years. In 2019 the median age had increased to 38.3 years.
Jefferson County had the highest median age in 2010 at 53.9 years. By 2019, the median age in Jefferson County had reached 58.9 years.
Washington state population by age group
Census 2010
OFM 2011 through 2020 estimates are based on 2010 census data. Results from the 2020 Census are not available yet. OFM Small Area Demographic Estimates from 2011 forward will be revised after detailed 2020 Census data are released.
- Projections, 2010-2040: State | State (ages 15-19 by single year)