90% of Illinois communities lost population in 2020

Census estimates predict nearly all Illinois municipalities shed population last year, with a greater share of large communities being affected.

Illinoisans already knew the state shrank for the seventh consecutive year – at least according to Census Bureau estimates. Then they learned all the large metro areas shrank. Now the latest estimates for all communities show 90% lost people.

Data released May 27 by the U.S. Census Bureau estimates that 1,170 communities across the state experienced population decline from July 2019-July 2020, with larger municipalities experiencing population decline most often.

While population loss during the decade has affected a greater share of smaller communities, more recent data shows all of the state’s large cities are shrinking and municipalities of all sizes are now being affected by population decline at similar rates.

This comes after the 2020 official Census count confirmed Illinois for the first time in 200 years lost population, officially dropping Illinois to the sixth-largest state behind Pennsylvania. Apportionment counts revealed Illinois would lose a seat in Congress. However, it should be noted that there are discrepancies between the Census Bureau’s estimates of the population and their official decennial Census count, which showed a much smaller statewide population loss of 18,124 that hasn’t yet been addressed by the Census Bureau.

Not only are larger municipalities now more likely to experience population decline, they also contribute most to the state’s declining population.

While Illinois’ large cities are most likely to experience population decline and contribute most to the state’s total decline in population, smaller communities are shrinking the fastest.

The estimates released May 27 offer insights into where population decline is occurring the most, but questions over the accuracy of the estimates have been raised on numerous occasions in recent years. One of the primary ways the Census Bureau checks the official head count is to compare it with their previous estimates.

It is also unclear what effect Illinois’ increased census outreach spending, which was second highest in the nation, had on the official results. It is possible increased spending resulted in a more accurate count in 2020 than in 2010, which could explain the difference between the official count and estimates. The 2020 estimates are based on the 2010 official count.

This wouldn’t be the first time improvements in the Census process have resulted in official counts that are different from the estimates. It is also likely the estimated geographic trends in population change are still relatively accurate, just that the 2010 base population level was incorrect.

While official Census counts of the population across the state have yet to be released, lawmakers are continuing to push forward with a map making process which depends on the estimates rather than the yet-to-be-released, detailed data from the actual 2020 U.S. Census. Their first draft of Illinois’ new legislative maps have already drawn criticisms of gerrymandering from the minority GOP and 13 good government groups, incliuding the League of Women Voters. However, Gov. J.B. Pritzker has now backed off of his campaign promise to veto new partisan, gerrymandered maps.

Without official, detailed data on the state population, it is impossible to determine whether the proposed legislative boundaries are of roughly equal size and ensure fairness in representation, as required by federal law. It is also clear that whatever maps are ultimately approved by Pritzker are likely to be highly partisan and face lengthy legal challenges.