Fastest-growing counties in Illinois

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From 2019 to 2020, the U.S. population grew by .35%, its slowest rate since 1900. Declining births, increasing deaths largely due to the graying Baby Boomer population, and a crackdown on immigration have contributed to many states seeing net population losses in recent years.

But in other pockets of the country, populations are growing. These shifts can be due to job opportunities, high quality of life, easy commutability to job centers, low rents, or any combination of these or other factors. Stacker compiled a list of the fastest-growing counties in Illinois using data from the U.S. Census Bureau. Counties are ranked by the highest population growth from 2010 to 2020.

A county typically sees population growth as a “bedroom community” (a municipality with an atypically large commuting population) to a large city. These communities are typically quieter than their feeder cities, offer lower rents and a higher quality of living, and are remote enough to be immune to the feeder city’s crime, traffic, and crowds. Keep reading to see if your home county made the list.

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#49. White County

- 2010 to 2020 population change: -923

--- #2,464 among all counties nationwide

- 2010 to 2020 percent population change: -6.2%

--- #63 among counties in Illinois, #2,499 among all counties nationwide

- 2020 population: 13,877

--- #76 largest county in Illinois, #2,164 largest county nationwide

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#48. Warren County

- 2010 to 2020 population change: -910

--- #2,459 among all counties nationwide

- 2010 to 2020 percent population change: -5.1%

--- #48 among counties in Illinois, #2,322 among all counties nationwide

- 2020 population: 16,835

--- #63 largest county in Illinois, #1,979 largest county nationwide

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#47. Christian County

- 2010 to 2020 population change: -904

--- #2,454 among all counties nationwide

- 2010 to 2020 percent population change: -2.6%

--- #31 among counties in Illinois, #1,957 among all counties nationwide

- 2020 population: 34,032

--- #43 largest county in Illinois, #1,328 largest county nationwide

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#46. Mercer County

- 2010 to 2020 population change: -852

--- #2,430 among all counties nationwide

- 2010 to 2020 percent population change: -5.1%

--- #49 among counties in Illinois, #2,325 among all counties nationwide

- 2020 population: 15,699

--- #69 largest county in Illinois, #2,048 largest county nationwide

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#45. Gallatin County

- 2010 to 2020 population change: -827

--- #2,412 among all counties nationwide

- 2010 to 2020 percent population change: -14.3%

--- #96 among counties in Illinois, #3,018 among all counties nationwide

- 2020 population: 4,946

--- #99 largest county in Illinois, #2,829 largest county nationwide

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#44. Wabash County

- 2010 to 2020 population change: -780

--- #2,389 among all counties nationwide

- 2010 to 2020 percent population change: -6.4%

--- #66 among counties in Illinois, #2,529 among all counties nationwide

- 2020 population: 11,361

--- #86 largest county in Illinois, #2,324 largest county nationwide

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#43. Hardin County

- 2010 to 2020 population change: -753

--- #2,373 among all counties nationwide

- 2010 to 2020 percent population change: -17.1%

--- #101 among counties in Illinois, #3,079 among all counties nationwide

- 2020 population: 3,649

--- #102 largest county in Illinois, #2,914 largest county nationwide

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#42. Union County

- 2010 to 2020 population change: -715

--- #2,343 among all counties nationwide

- 2010 to 2020 percent population change: -4.0%

--- #40 among counties in Illinois, #2,166 among all counties nationwide

- 2020 population: 17,244

--- #61 largest county in Illinois, #1,952 largest county nationwide

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#41. Jo Daviess County

- 2010 to 2020 population change: -693

--- #2,327 among all counties nationwide

- 2010 to 2020 percent population change: -3.0%

--- #33 among counties in Illinois, #2,021 among all counties nationwide

- 2020 population: 22,035

--- #53 largest county in Illinois, #1,713 largest county nationwide

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#40. Stark County

- 2010 to 2020 population change: -686

--- #2,317 among all counties nationwide

- 2010 to 2020 percent population change: -11.3%

--- #90 among counties in Illinois, #2,917 among all counties nationwide

- 2020 population: 5,400

--- #95 largest county in Illinois, #2,787 largest county nationwide

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#39. Calhoun County

- 2010 to 2020 population change: -681

--- #2,313 among all counties nationwide

- 2010 to 2020 percent population change: -13.3%

--- #94 among counties in Illinois, #2,989 among all counties nationwide

- 2020 population: 4,437

--- #100 largest county in Illinois, #2,861 largest county nationwide

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#38. Wayne County

- 2010 to 2020 population change: -667

--- #2,300 among all counties nationwide

- 2010 to 2020 percent population change: -4.0%

--- #39 among counties in Illinois, #2,160 among all counties nationwide

- 2020 population: 16,179

--- #66 largest county in Illinois, #2,022 largest county nationwide

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#37. Pope County

- 2010 to 2020 population change: -663

--- #2,297 among all counties nationwide

- 2010 to 2020 percent population change: -15.0%

--- #98 among counties in Illinois, #3,036 among all counties nationwide

- 2020 population: 3,763

--- #101 largest county in Illinois, #2,903 largest county nationwide

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#36. Brown County

- 2010 to 2020 population change: -653

--- #2,290 among all counties nationwide

- 2010 to 2020 percent population change: -9.5%

--- #83 among counties in Illinois, #2,813 among all counties nationwide

- 2020 population: 6,244

--- #93 largest county in Illinois, #2,719 largest county nationwide

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#35. Clay County

- 2010 to 2020 population change: -639

--- #2,281 among all counties nationwide

- 2010 to 2020 percent population change: -4.6%

--- #45 among counties in Illinois, #2,240 among all counties nationwide

- 2020 population: 13,288

--- #80 largest county in Illinois, #2,197 largest county nationwide

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#34. Schuyler County

- 2010 to 2020 population change: -625

--- #2,273 among all counties nationwide

- 2010 to 2020 percent population change: -8.3%

--- #80 among counties in Illinois, #2,719 among all counties nationwide

- 2020 population: 6,902

--- #90 largest county in Illinois, #2,667 largest county nationwide

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#33. Cumberland County

- 2010 to 2020 population change: -623

--- #2,270 among all counties nationwide

- 2010 to 2020 percent population change: -5.6%

--- #57 among counties in Illinois, #2,401 among all counties nationwide

- 2020 population: 10,450

--- #87 largest county in Illinois, #2,382 largest county nationwide

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#32. Cass County

- 2010 to 2020 population change: -606

--- #2,260 among all counties nationwide

- 2010 to 2020 percent population change: -4.4%

--- #44 among counties in Illinois, #2,217 among all counties nationwide

- 2020 population: 13,042

--- #82 largest county in Illinois, #2,212 largest county nationwide

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#31. Ford County

- 2010 to 2020 population change: -579

--- #2,230 among all counties nationwide

- 2010 to 2020 percent population change: -4.1%

--- #42 among counties in Illinois, #2,180 among all counties nationwide

- 2020 population: 13,534

--- #78 largest county in Illinois, #2,183 largest county nationwide

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#30. Fayette County

- 2010 to 2020 population change: -519

--- #2,191 among all counties nationwide

- 2010 to 2020 percent population change: -2.4%

--- #29 among counties in Illinois, #1,922 among all counties nationwide

- 2020 population: 21,488

--- #55 largest county in Illinois, #1,741 largest county nationwide

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#29. Clinton County

- 2010 to 2020 population change: -496

--- #2,167 among all counties nationwide

- 2010 to 2020 percent population change: -1.3%

--- #21 among counties in Illinois, #1,758 among all counties nationwide

- 2020 population: 36,899

--- #38 largest county in Illinois, #1,256 largest county nationwide

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#28. Jasper County

- 2010 to 2020 population change: -465

--- #2,136 among all counties nationwide

- 2010 to 2020 percent population change: -4.8%

--- #46 among counties in Illinois, #2,268 among all counties nationwide

- 2020 population: 9,287

--- #88 largest county in Illinois, #2,468 largest county nationwide

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#27. Edwards County

- 2010 to 2020 population change: -462

--- #2,133 among all counties nationwide

- 2010 to 2020 percent population change: -6.9%

--- #71 among counties in Illinois, #2,585 among all counties nationwide

- 2020 population: 6,245

--- #92 largest county in Illinois, #2,718 largest county nationwide

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#26. Hamilton County

- 2010 to 2020 population change: -460

--- #2,129 among all counties nationwide

- 2010 to 2020 percent population change: -5.4%

--- #54 among counties in Illinois, #2,371 among all counties nationwide

- 2020 population: 7,993

--- #89 largest county in Illinois, #2,579 largest county nationwide

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#25. Scott County

- 2010 to 2020 population change: -425

--- #2,087 among all counties nationwide

- 2010 to 2020 percent population change: -7.9%

--- #74 among counties in Illinois, #2,686 among all counties nationwide

- 2020 population: 4,949

--- #98 largest county in Illinois, #2,828 largest county nationwide

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#24. Menard County

- 2010 to 2020 population change: -405

--- #2,064 among all counties nationwide

- 2010 to 2020 percent population change: -3.2%

--- #34 among counties in Illinois, #2,042 among all counties nationwide

- 2020 population: 12,297

--- #83 largest county in Illinois, #2,256 largest county nationwide

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#23. Richland County

- 2010 to 2020 population change: -353

--- #1,996 among all counties nationwide

- 2010 to 2020 percent population change: -2.2%

--- #28 among counties in Illinois, #1,900 among all counties nationwide

- 2020 population: 15,813

--- #67 largest county in Illinois, #2,041 largest county nationwide

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#22. Putnam County

- 2010 to 2020 population change: -345

--- #1,988 among all counties nationwide

- 2010 to 2020 percent population change: -5.8%

--- #58 among counties in Illinois, #2,420 among all counties nationwide

- 2020 population: 5,637

--- #94 largest county in Illinois, #2,769 largest county nationwide

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#21. Douglas County

- 2010 to 2020 population change: -272

--- #1,906 among all counties nationwide

- 2010 to 2020 percent population change: -1.4%

--- #23 among counties in Illinois, #1,766 among all counties nationwide

- 2020 population: 19,740

--- #58 largest county in Illinois, #1,831 largest county nationwide

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#20. Moultrie County

- 2010 to 2020 population change: -197

--- #1,810 among all counties nationwide

- 2010 to 2020 percent population change: -1.3%

--- #22 among counties in Illinois, #1,763 among all counties nationwide

- 2020 population: 14,526

--- #74 largest county in Illinois, #2,116 largest county nationwide

Teemu008 from Palatine, Illinois // Wikimedia Commons

#19. Boone County

- 2010 to 2020 population change: -119

--- #1,706 among all counties nationwide

- 2010 to 2020 percent population change: -0.2%

--- #19 among counties in Illinois, #1,603 among all counties nationwide

- 2020 population: 53,448

--- #25 largest county in Illinois, #943 largest county nationwide

Dual Freq // Wikimedia Commons

#18. Piatt County

- 2010 to 2020 population change: -35

--- #1,607 among all counties nationwide

- 2010 to 2020 percent population change: -0.2%

--- #18 among counties in Illinois, #1,599 among all counties nationwide

- 2020 population: 16,673

--- #65 largest county in Illinois, #1,992 largest county nationwide

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#17. Carroll County

- 2010 to 2020 population change: 87

--- #1,475 among all counties nationwide

- 2010 to 2020 percent population change: +0.6%

--- #16 among counties in Illinois, #1,485 among all counties nationwide

- 2020 population: 15,702

--- #68 largest county in Illinois, #2,047 largest county nationwide

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#16. Woodford County

- 2010 to 2020 population change: 241

--- #1,374 among all counties nationwide

- 2010 to 2020 percent population change: +0.6%

--- #15 among counties in Illinois, #1,475 among all counties nationwide

- 2020 population: 38,467

--- #34 largest county in Illinois, #1,213 largest county nationwide

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#15. Effingham County

- 2010 to 2020 population change: 436

--- #1,263 among all counties nationwide

- 2010 to 2020 percent population change: +1.3%

--- #14 among counties in Illinois, #1,397 among all counties nationwide

- 2020 population: 34,668

--- #41 largest county in Illinois, #1,308 largest county nationwide

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#14. Johnson County

- 2010 to 2020 population change: 598

--- #1,185 among all counties nationwide

- 2010 to 2020 percent population change: +4.7%

--- #4 among counties in Illinois, #968 among all counties nationwide

- 2020 population: 13,308

--- #79 largest county in Illinois, #2,195 largest county nationwide

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#13. Sangamon County

- 2010 to 2020 population change: 1,055

--- #1,068 among all counties nationwide

- 2010 to 2020 percent population change: +0.5%

--- #17 among counties in Illinois, #1,487 among all counties nationwide

- 2020 population: 196,343

--- #11 largest county in Illinois, #345 largest county nationwide

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#12. Williamson County

- 2010 to 2020 population change: 1,574

--- #958 among all counties nationwide

- 2010 to 2020 percent population change: +2.4%

--- #10 among counties in Illinois, #1,232 among all counties nationwide

- 2020 population: 67,153

--- #22 largest county in Illinois, #798 largest county nationwide

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#11. Monroe County

- 2010 to 2020 population change: 2,531

--- #817 among all counties nationwide

- 2010 to 2020 percent population change: +7.8%

--- #2 among counties in Illinois, #709 among all counties nationwide

- 2020 population: 34,962

--- #40 largest county in Illinois, #1,300 largest county nationwide

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#10. Grundy County

- 2010 to 2020 population change: 3,789

--- #708 among all counties nationwide

- 2010 to 2020 percent population change: +7.8%

--- #3 among counties in Illinois, #711 among all counties nationwide

- 2020 population: 52,533

--- #27 largest county in Illinois, #958 largest county nationwide

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#9. McHenry County

- 2010 to 2020 population change: 4,179

--- #679 among all counties nationwide

- 2010 to 2020 percent population change: +1.4%

--- #13 among counties in Illinois, #1,384 among all counties nationwide

- 2020 population: 310,229

--- #6 largest county in Illinois, #230 largest county nationwide

Michael from Palatine, Illinois // Wikimedia Commons

#8. McLean County

- 2010 to 2020 population change: 4,248

--- #673 among all counties nationwide

- 2010 to 2020 percent population change: +2.5%

--- #8 among counties in Illinois, #1,210 among all counties nationwide

- 2020 population: 170,954

--- #13 largest county in Illinois, #388 largest county nationwide

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#7. Champaign County

- 2010 to 2020 population change: 7,998

--- #526 among all counties nationwide

- 2010 to 2020 percent population change: +4.0%

--- #6 among counties in Illinois, #1,026 among all counties nationwide

- 2020 population: 205,865

--- #10 largest county in Illinois, #333 largest county nationwide

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#6. Kane County

- 2010 to 2020 population change: 13,894

--- #398 among all counties nationwide

- 2010 to 2020 percent population change: +2.8%

--- #7 among counties in Illinois, #1,185 among all counties nationwide

- 2020 population: 516,522

--- #5 largest county in Illinois, #140 largest county nationwide

edward P. steinburg desnged // Wikimedia Commons

#5. Lake County

- 2010 to 2020 population change: 17,163

--- #355 among all counties nationwide

- 2010 to 2020 percent population change: +2.5%

--- #9 among counties in Illinois, #1,224 among all counties nationwide

- 2020 population: 714,342

--- #3 largest county in Illinois, #97 largest county nationwide

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#4. DuPage County

- 2010 to 2020 population change: 21,396

--- #318 among all counties nationwide

- 2010 to 2020 percent population change: +2.3%

--- #11 among counties in Illinois, #1,238 among all counties nationwide

- 2020 population: 932,877

--- #2 largest county in Illinois, #59 largest county nationwide

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#3. Kendall County

- 2010 to 2020 population change: 26,267

--- #271 among all counties nationwide

- 2010 to 2020 percent population change: +24.9%

--- #1 among counties in Illinois, #115 among all counties nationwide

- 2020 population: 131,869

--- #15 largest county in Illinois, #489 largest county nationwide

Teemu008 from Palatine, Illinois // Wikimedia Commons

#2. Will County

- 2010 to 2020 population change: 28,378

--- #256 among all counties nationwide

- 2010 to 2020 percent population change: +4.2%

--- #5 among counties in Illinois, #1,004 among all counties nationwide

- 2020 population: 696,355

--- #4 largest county in Illinois, #98 largest county nationwide

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#1. Cook County

- 2010 to 2020 population change: 102,693

--- #61 among all counties nationwide

- 2010 to 2020 percent population change: +2.0%

--- #12 among counties in Illinois, #1,290 among all counties nationwide

- 2020 population: 5,275,541

--- #1 largest county in Illinois, #2 largest county nationwide