Illinois loses 1 seat in Congress after 2020 Census shows first population drop in 200 years

Illinois loses 1 seat in Congress after 2020 Census shows first population drop in 200 years

Illinois will lose one representative in the U.S. House. The state’s population declined for the first time in over 200 years, the 10-year U.S. Census count showed.

Illinois’ population count was 12,812,508 in 2020, a drop of 18,124 since 2010, according to new data released April 26 by the U.S. Census Bureau. The data confirmed a long-held fear for Illinoisans: population decline means Illinois will again lose a seat in Congress.

It also means Illinois for the first time in 200 years lost population in the decennial U.S. Census count.

During the past decade, Illinois suffered the second-largest population decline in numeric terms, behind only West Virginia. As a percentage of the population, Illinois’ population decline was third worst behind West Virginia and Mississippi.

Historical data shows domestic outmigration – moving to and from other states – has been the sole driver of Illinois’ population decline. Major reasons Illinoisans are choosing to leave the state are for better housing and employment opportunities, both of which have been made worse by poor public policy in Illinois. Nearly half of Illinoisans have thought about moving away, and they said taxes were their No. 1 reason. Population decline also contributes to the lower economic prospects of the state.

Illinois’ population decline will affect more than just the economy. The state will lose a representative in the U.S. House.

Seven states lost representatives, with California, Illinois, Michigan, New York, Ohio, Pennsylvania and West Virginia each losing one seat. Six states gained seats. Texas added two seats. Colorado, Florida, Montana, North Carolina, and Oregon each added one seat.

These Census numbers do not give the details necessary for Illinois to use the data for redistricting, but it is likely the population of Chicago’s collar counties, and therefore their representation in legislative and congressional districts, will increase relative to Cook County and downstate Illinois. Those areas will lose representation, with few exceptions.


Never in its history has Illinois lost population in the once-a-decade population count – until the 2020 count. It lost 10 representatives since the 1930 count as its growth has lagged other states, but it has not seen an actual decline until now.

Census numbers have been delayed because of COVID-19. The loss of a congressional seat and the delay of census numbers leaves aspiring candidates for the U.S. House of Representatives in a difficult situation because district boundaries may not be drawn with much time before candidate filing deadlines.

Congressional redistricting is especially strict, requiring districts as close to equal in population as practical, meaning there is virtually no way to draw districts without the official Census numbers. Candidates cannot know what the districts will look like until after the Illinois General Assembly passes a map and Gov. J.B. Pritzker signs it into law.

Because the detailed numbers are not expected to be available until late summer, candidates will be scrambling to gather the required signatures to meet the Nov. 29 filing deadline under the current election code. No one will know which representative’s district will be eliminated, though with supermajorities in the Illinois House, Illinois Senate and control of the governor’s office, it is a safe bet Democrats will target a Republican-held seat unless Pritzker follows through on his promise to veto any partisan, gerrymandered map.

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