Is Illinois's population growing or shrinking?
Updated annually
It grew by 16,100 between 2024 and 2025. Changes in population reflect birth and death rates, immigration patterns, regional shifts, and even the overall health of the economy. Illinois’s 0.13% annual increase was primarily driven by immigration to the state. In the decade between 2015 and 2025, Illinois’s population declined by 1.9%.
+16.1K
population change (2024 to 2025)
+0.13%
percent change in population (2024 to 2025)
Since 2000, Illinois' population increased in 17 of 25 years. The largest increase occurred between 2023 and 2024, when it gained 69,600 residents. The state's largest decline during the 21st century occurred between 2021 and 2022 when it lost 93,800 residents.
Illinois gained 16,100 residents between 2024 and 2025.
Annual population change
A state’s population is influenced by three factors:
- Natural population change: If births outnumber deaths in a given year, natural population growth is positive. If deaths exceed births, it is negative. Between 2024 to 2025 natural population change was positive in Illinois, with births exceeding deaths by 10,900.
- Immigration: international migration directly into or out of a state. If more people move in than move out, population change from immigration is positive. If more people move out than move in, it’s negative. Illinois’s population change from immigration was positive, with about 44,800 more people coming from another country to Illinois than leaving.
- Domestic migration, moving between states: Illinois’s population change from domestic migration was negative, with about 40,000 more people leaving for another state than moving in.
Between 2024 and 2025, immigration was the primary driver of population growth in Illinois.
Components of population change
Among 102 county equivalents, Cook County had the largest population growth in Illinois, welcoming 40,095 new residents. St. Clair County lost the most, with a loss of 945 residents. County-level population data is available as of 2024.
Kendall County led Illinois in percent population increase between 2023 and 2024 at 2.1 percent. Alexander County ranked last with a 2.7 percent decline.
Between 2023 and 2024, Kendall County gained 2.1% in population, the largest increase in Illinois.
Population change
Between 2015 and 2025, Illinois’s population has declined by -1.9%. During that same period, the US population grew by 6.2%. Illinois ranks 49th among states in population growth over that decade.
Illinois ranked 49th in population growth between 2015 and 2025.
Percent change in population
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Methodology
USAFacts standardizes data, in areas such as time and demographics, to make it easier to understand and compare.
The analysis was generated with the help of AI and reviewed by USAFacts for accuracy.
Page sources
USAFacts endeavors to share the most up-to-date information available. We sourced the data on this page directly from government agencies; however, the intervals at which agencies publish updated data vary.
