Despite a slight overall population increase due to international migration and births exceeding deaths, Illinois continues to experience a significant outflow of residents to other states. Released on Thursday, new Census Bureau estimates reveal a complex demographic picture for the state.
Illinois Population Trends
Eight of the eleven metro areas in Illinois, and more than half of its counties, saw net outmigration in the year ending July 1, 2025. In total, Illinois lost over 40,000 residents to other states during that period. However, nearly 45,000 international migrants and roughly 11,000 more births than deaths partially offset this loss, resulting in a marginal overall population gain.
The Chicago-Naperville-Schaumburg metropolitan area experienced the largest domestic outmigration, with over 35,000 residents leaving last year. Champaign-Urbana saw the next-largest loss, with 2,118 residents moving away. Rockford was the only metro area to observe growth due to domestic migration, international migration, and more births than deaths.
While some areas benefited from international migration, others experienced population decline due to a combination of domestic outmigration and more deaths than births. Peoria, Decatur, and Kankakee all saw both domestic outmigration and overall population decline. The Illinois portion of the St. Louis metro area experienced a net decrease of 914 residents despite some domestic in-migration.
Fifty-five of Illinois’ 102 counties experienced outmigration last year, contributing to population decline in 64 counties. Chicago-area counties saw the largest domestic migration losses, with Cook County losing 31,114 residents, DuPage County losing 5,854, and Lake County losing 3,176.
Downstate counties are experiencing the fastest rates of population decline from domestic outmigration, particularly Cass, Edwards, and Champaign counties. Bond County, however, saw the fastest rate of domestic in-migration, gaining nearly 24 migrants per 1,000 residents.
Frequently Asked Questions
What is the overall population trend in Illinois?
Illinois’ total population grew marginally due to nearly 45,000 international migrants and roughly 11,000 more births than deaths, despite losing more than 40,000 residents to other states in 2025.
Which areas of Illinois are experiencing the most significant population loss?
Eight of 11 metro areas and more than half of the state’s counties saw net outmigration. The Chicago-Naperville-Schaumburg metropolitan area experienced the largest loss, with over 35,000 residents leaving last year.
What is the primary reason Illinoisans are leaving the state, according to recent data?
Recent data suggests high taxes are a primary reason Illinoisans are leaving, with 95% of those who left in 2024 moving to states with lower tax burdens.
As Illinois lawmakers consider further tax increases, including potential taxes on retirees, the ongoing outflow of residents raises questions about the state’s future economic trajectory. Will Illinois be able to address the concerns driving residents away, or will the trend of outmigration continue?
