The District’s adult population (age 18 and over) grew by 9.6% from 2000 and 2010 and another 12.7% from 2010 to 2020. Census estimates show a 2.7% decline in 2021, the first year of COVID-19, followed by steady annual increases through 2025, although growth in 2025 was only about half of the prior year's increase. The District's youth (under age 18) grew by 24% between 2010 and 2020, then declined by 3.7% in 2021. It increased each year from 2022 through 2024, but the Census estimates a slight decrease of 0.3% in 2025.
Adult and Child Population Trends in the District of Columbia, 1990-2025
Sources: US Census Bureau, Decennial Counts and Population Estimates
The number of children under age 5 increased by approximately 9,700 children or 30% between 2010 and 2020. Since 2020, the estimated number of children under age of 5 has steadily decreased prompted by the COVID-19 pandemic as well as the decreased number of births. Like young children, 5 to 13 year olds increased by 35% between 2010 and 2020. While the first year of the pandemic resulted in fewer 5 to 13 year olds in 2021, Census estimates the number to steadily increase since. The 14 to 17 year olds, or high school students, decreased between 2010 and 2020 but are estimated to have increased annually since.
Child Population by Age Groups in the District of Columbia, 1990-2025
Sources: US Census Bureau, Decennial Census and Population Estimates
The 18 to 34 year old age group or "millennials” grew by more than 37,300 (or 21%) between 2000 and 2010 and then by another 17,000 (or 8%) more between 2010 and 2020. The number of millennials were estimated to have decreased during the coronavirus (COVID-19) pandemic holding relatively flat each year since. The 35 to 64 year old group increased by approximately 30,400 residents (14%) between 2010 and 2020. After the decrease experienced during the first year of the pandemic in 2021, this age group is estimated to modestly increase each year since. The 65+ age group not only increased between 2010 and 2020 (by approximately 16,000 residents) but are estimated to have increased modestly during and after the COVID-19 pandemic as well.
Adult Population by Age Groups in the District of Columbia, 1990-2025
Sources: US Census Bureau, Decennial Census and Population Estimates
