Illinois lost nearly 214,000 residents under the age of 20 between 2020 and 2025, a decline of 6.8% that outpaced the national average by more than three times, according to newly released Census Bureau data analyzed by the Illinois Policy Institute. The report, published in 2025, highlights a sharp demographic shift that should concern state leaders as the state's age profile diverges substantially from national trends. While the U.S. as a whole saw its under-20 population decline by just 2% during the same period, Illinois' young population dropped by more than 36,000 in 2024 alone.
The demographic changes extend across multiple age groups, with Illinois consistently lagging behind national growth rates. From 2020 to 2025, the population of Illinoisans in their 20s grew by only 1%, compared with 4.3% nationally. Those in their 30s increased by a mere 0.5% in Illinois versus 4.7% across the U.S., while the state's population in their 40s grew by just 1.2% against a national rate of 5.5%. Meanwhile, Illinois' older population surged, with residents 60 and over increasing by 8.2% (more than 240,000 people) compared with 11% nationally. The state's median age has risen to 39.7, just above the national median of 39.4. Both Illinois and the nation saw declines in their 50-something populations as Baby Boomers aged into their 60s.
Despite the overall population drain among younger residents, Illinois did see modest population growth in 2025, gaining 16,108 residents driven by increases of 32,343 Hispanic and 18,171 Asian residents. However, the state lost more than 40,000 residents to outmigration in the same year. The report notes that the surge in Hispanic residents is driven primarily by higher birth rates among that demographic group, while international migration contributed nearly 45,000 new residents. Since 2020, the state's white population has declined by 191,201 (2.0%) and its Black population by 44,490 (2.3%), while Hispanic residents jumped by 184,125 (7.9%) and Asian residents by 107,408 (13.8%). The report emphasizes that previous analysis found Illinois losing residents of all backgrounds to domestic outmigration, meaning growth in Hispanic and Asian populations is likely due to natural increases and international migration rather than people moving from other states.
The report identifies Illinois' tax burden as a key driver behind the exodus. According to the analysis, 95% of those who moved out of Illinois in 2024 relocated to states with lower tax burdens. The report also cites recent polling showing that over half of Illinoisans would leave the state if given the opportunity. While the population changes in Illinois and the U.S. trend in the same direction—both seeing younger populations decline and older populations grow—the state is experiencing much more substantial shifts in its age profile. The report explains that these differences are likely due to outmigration trends, as both retirees and younger families are leaving Illinois in greater numbers than the national average. The combination of losing young people at an accelerated rate while seeing slower growth in working-age populations compared with the rest of the country signals a deepening demographic crisis.
The report concludes that the large decline in Illinois' young population and substantially slower growth across other age groups should prompt state leaders to work on solutions, starting with reining in the state's tax environment. Without changes to address the factors driving residents away—particularly the state's high tax burden—the authors warn that Illinois' population crisis will escalate quickly. The data reveals a state losing its future workforce and families at an alarming rate, replaced only by natural population increases in certain demographic groups and international migration that can't fully offset the domestic outflow.