The number of state residents under 20 fell 6.8% from 2020 to 2025.
A sharp decline in young people in Illinois and other newly released age data should concern state leaders and spur work on solutions.
From 2020 to 2025, Illinois’ population of residents under 20 fell by 6.8%, more than three times faster than the national average of 2%, according to the U.S. Census Bureau.
The number of state residents under 20 fell by over 36,000 last year and nearly 214,000 since 2020.
Meanwhile, the population of older Illinoisans saw a large increase in that time. The number of those 60 and older rose by more than 46,387 last year and more than 240,000 since 2020.
Both nationally and in Illinois the number of residents in their 50s declined as the large Baby Boomer generation has aged. The population of those 60 and over increased by 11% nationally and 8.2% in Illinois from 2020 to 2025.
Other younger age groups also are growing far faster across the nation than in Illinois. From 2020 to 2025:
- The population of those in their 20s grew by 4.3% nationally but only 1% in Illinois.
- The number of 30-somethings grew by 4.7% in the U.S. but a mere 0.5% in Illinois.
- The population in their 40s grew by 5.5% nationally but only 1.2% in Illinois.
The state’s median age has increased to 39.7, slightly above the national median of 39.4.
While the population changes by age trends in the U.S. and Illinois are similar in directionality, the state is seeing more substantial shifts in its age profile. These differences are likely due to outmigration trends in Illinois, as a net number of retirees and younger families are moving out of the state. Thus while Illinois’ median age might closely track the national figure today, the state’s population changes are much more concerning than what the nation as a whole is experiencing.
Illinois’ population did increase in 2025
Illinois’ population growth of 16,108 residents last year was driven by an increase of 32,343 Hispanic and 18,171 Asian residents. The number of white Illinoisans declined by 10,243 last year and the number of Black Illinoisans fell by 2,883.
Since July 2020, the population of white Illinoisans has declined by 191,201 (2.0%) and the number of Black Illinoisans by 44,490 (2.3%).
The number of Hispanic Illinoisans jumped by 184,125 (7.9%) in that time, and the population of Asian Illinoisans by 107,408 (13.8%).
Other populations, including those of two or more races, increased by 52,076 (7.3%).
The surge in Hispanic residents in Illinois is driven primarily by higher birth rates among that group than other demographic groups in the state. International migration also likely contributes, as Illinois gained nearly 45,000 international migrants last year alone.
While the Census Bureau did not make data available on the reasons for Illinois’ 2025 population changes by demographic group, previous analysis found that the state was losing residents of all backgrounds to domestic outmigration. In other words, growth in Illinois’ Hispanic and Asian populations is likely attributable to natural increases — births minus deaths — and international migration.
Despite the slight population growth in 2025, Illinois lost more than 40,000 residents last year to outmigration. Recent polling suggests that over half of Illinoisans would leave the state if they had the opportunity.
Census Bureau data sheds light on one potential reason so many Illinoisans leave: high taxes. In 2024, 95% of those who moved out fled to states with lower tax burdens.
The large decline in Illinois’ young population and the substantially slower growth in other age groups compared with the national average should show how pressing the state’s population issue has become. The data should prompt state leaders to work on solutions, starting with reigning in Illinois’ cumbersome tax environment.
Without such changes, Illinois’ population crisis will escalate quickly.
