Illinois sees second-largest population loss of U.S. states
Illinois lost nearly 80,000 residents in 2020, marking the seventh straight year of population decline, according to new estimates from the U.S. Census Bureau.
Illinois’ population is now 12,587,530, a decline of almost 2 percent since the beginning of the decade. Over that time period, West Virginia was the only state to see a higher rate of population loss.
The new population data come from the U.S. Census Bureau’s 2020 Population Estimates, released in late December 2020. The estimates are not based on the results of the 2020 census, which are not yet available. The Chicago Metropolitan Agency for Planning (CMAP) has analyzed recent census estimates to provide a deeper look at population trends across both Illinois and the seven-county CMAP region.
How the Chicago region compares to the rest of Illinois
At the regional level, the population of metropolitan Chicago remained essentially stagnant: The population declined by less than 0.1 percent in recent years, when comparing five-year averages from 2010-2014 and 2015-2019.
The vast majority of Illinois’ population losses have occurred outside of the seven-county CMAP region. The region is also home to four of the nine Illinois counties that saw population growth over this time period: DuPage, Kane, Kendall, and Will. While Cook, Lake, and McHenry counties saw small declines, they lost a significantly smaller share of their population compared to nearly all the other counties in the state. Still, while northeastern Illinois’ growth rate is stronger than the state as a whole, the rate is much lower than that of other major metropolitan areas. Compared to the 50 largest metropolitan areas in the U.S., the Chicago region had the 46th-lowest growth rate — ahead only of other industrial Midwestern and Northeastern regions like Pittsburgh, PA, and Hartford, CT. Meanwhile, areas like Austin, TX; Orlando, FL; and Houston, TX, saw growth rates of more than 10 percent. Population trends within the region have fluctuated among different demographic groups. For example, the Hispanic population in northeastern Illinois — historically a strong driver of regional population growth — has continued to grow. However, the growth rate is only 47th among the country’s 50 largest metropolitan areas.
Where residents are moving to (and coming from) In 2019, more than 308,000 Illinois residents moved to other U.S. states, Washington, D.C., and Puerto Rico, according to census estimates. The top destinations were neighboring and high-population states, including Indiana, Florida, California, Texas, and Wisconsin. Four of those states — Indiana, Florida, California, and Wisconsin — were also the top sources of people moving to Illinois. Still, the 248,000 new
residents, either from elsewhere in the U.S. or abroad, were not enough to offset those who left. In northeastern Illinois, one source of continued population growth has been migration from abroad. However, the rate of that growth appears to have slowed. While some groups, such as residents born in India, have seen significant growth, those gains have been almost entirely offset by declines in other groups, such as residents of the region born in Mexico.
Looking ahead
ON TO 2050, the region’s long-range plan, aims to promote inclusive growth. Understanding population trends is critical to developing policies and programs that support communities throughout northeastern Illinois.
CMAP will continue to monitor updated population data as new estimates become available, including the results of the 2020 census. The U.S. Census Bureau failed to meet a legal deadline of December 31, 2020, to provide state-level population totals to Congress, which are used to redistribute congressional seats. Those results may not be available until March or later. Meanwhile, more detailed results — such as populations at the county level or smaller — are scheduled for release between March and August 2021.
In the coming months, CMAP looks forward to sharing regional analyses, policy briefs, and other insights based on the results.
About the data
The datasets used to develop this analysis are products of the U.S. Census Bureau. Although some of the datasets extend into 2020, none of them are based on the yet-to-be-released 2020 census. As of the publication of this piece, the Bureau has not released any results from the 2020 census. The 2020 state- level population estimates are instead the final state-level population estimates based on the 2010 census.
For county-level and metropolitan statistical area-level analyses, CMAP relied on five-year estimates from the American Community Survey (ACS). The ACS datasets, based on monthly surveys, provide a statistical estimate of various demographic, socioeconomic, and other population characteristics. ACS datasets are available in both one-year (e.g., 2019) and five-year (e.g., 2015-19) windows, with the five- year datasets providing more reliable and granular data for analysis. As a result, however, the five-year datasets also lag behind trends highlighted in one-year ACS data and point-in-time estimates, such as the 2020 Population Estimates. Readers should thus be cautious when evaluating trends identified in one-year estimates against those of five-year estimates, as the two are not directly comparable.
To complete this analysis, CMAP used application programming interfaces to directly download state- and county-level demographics and then used R, a free open source statistical package, to analyze the data. The R script used to perform this analysis is available on CMAP’s GitHub page. Others are encouraged to use and build on this analysis.