Why do people move from one county or region to another? The usual suspects are jobs, family, significant others, and overall cost of living, but there are other elements at play. For those with children, moving within close proximity of a highly rated school district is a key contributing factor. For younger adults just starting out, living someplace with a vibrant social scene might be a top priority. And for those whose careers have wound down after a lifetime of work, finding retirement-friendly communities is the goal—communities deemed to be safe, offer accessibility to medical resources and leisure activities in equal measure, and be affordable for those on a limited income.

This is, of course, by no means an exhaustive list. People’s reasons for choosing to live where they do are as diverse as people themselves.

As far as why certain counties across the U.S. have experienced growth, relocation is not the sole, or even primary, reason why. While more than 1,800 counties saw population gains in 2021, approximately 73% of all U.S. counties saw what the U.S. Census Bureau characterizes as a natural decrease. This was a significant jump from 2020, when 55.5% of countries experienced such a decrease. According to the Bureau, natural decrease is the simple result of “when there are more deaths than births in a population over a given time period.” In 2021, the conflation of fewer births with an aging population that was also absorbing a higher-than-usual mortality rate due to the ongoing COVID-19 pandemic led to this “increased decrease.”

Nonetheless, as stated 1,800 counties nationwide have grown larger over the last year, and a sizable percentage of them are in Missouri. Stacker compiled a list of the fastest-growing counties in Missouri using data from the U.S. Census Bureau. Counties are ranked by the highest population growth from 2010 to 2020, based on the U.S. Decennial Census.

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#50. Adair County

– 2010 to 2020 population change: -293
— #1,910 among all counties nationwide
– 2010 to 2020 percent population change: -1.1%
— #44 among counties in Missouri, #1,676 among all counties nationwide
– 2020 population: 25,314
— #41 largest county in Missouri, #1,591 largest county nationwide

#49. Shelby County

– 2010 to 2020 population change: -270
— #1,865 among all counties nationwide
– 2010 to 2020 percent population change: -4.2%
— #67 among counties in Missouri, #2,198 among all counties nationwide
– 2020 population: 6,103
— #104 largest county in Missouri, #2,731 largest county nationwide

#48. Marion County

– 2010 to 2020 population change: -256
— #1,850 among all counties nationwide
– 2010 to 2020 percent population change: -0.9%
— #43 among counties in Missouri, #1,638 among all counties nationwide
– 2020 population: 28,525
— #39 largest county in Missouri, #1,469 largest county nationwide

#47. Mercer County

– 2010 to 2020 population change: -247
— #1,840 among all counties nationwide
– 2010 to 2020 percent population change: -6.5%
— #81 among counties in Missouri, #2,548 among all counties nationwide
– 2020 population: 3,538
— #114 largest county in Missouri, #2,918 largest county nationwide

#46. Worth County

– 2010 to 2020 population change: -198
— #1,773 among all counties nationwide
– 2010 to 2020 percent population change: -9.1%
— #97 among counties in Missouri, #2,802 among all counties nationwide
– 2020 population: 1,973
— #115 largest county in Missouri, #3,042 largest county nationwide

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#45. Lewis County

– 2010 to 2020 population change: -179
— #1,741 among all counties nationwide
– 2010 to 2020 percent population change: -1.8%
— #52 among counties in Missouri, #1,801 among all counties nationwide
– 2020 population: 10,032
— #86 largest county in Missouri, #2,406 largest county nationwide

#44. Monroe County

– 2010 to 2020 population change: -174
— #1,733 among all counties nationwide
– 2010 to 2020 percent population change: -2.0%
— #53 among counties in Missouri, #1,841 among all counties nationwide
– 2020 population: 8,666
— #91 largest county in Missouri, #2,516 largest county nationwide

#43. Moniteau County

– 2010 to 2020 population change: -134
— #1,678 among all counties nationwide
– 2010 to 2020 percent population change: -0.9%
— #42 among counties in Missouri, #1,627 among all counties nationwide
– 2020 population: 15,473
— #67 largest county in Missouri, #2,062 largest county nationwide

#42. Scotland County

– 2010 to 2020 population change: -127
— #1,667 among all counties nationwide
– 2010 to 2020 percent population change: -2.6%
— #56 among counties in Missouri, #1,944 among all counties nationwide
– 2020 population: 4,716
— #109 largest county in Missouri, #2,838 largest county nationwide

#41. Callaway County

– 2010 to 2020 population change: -49
— #1,555 among all counties nationwide
– 2010 to 2020 percent population change: -0.1%
— #40 among counties in Missouri, #1,509 among all counties nationwide
– 2020 population: 44,283
— #24 largest county in Missouri, #1,090 largest county nationwide

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#40. Saline County

– 2010 to 2020 population change: -37
— #1,538 among all counties nationwide
– 2010 to 2020 percent population change: -0.2%
— #41 among counties in Missouri, #1,516 among all counties nationwide
– 2020 population: 23,333
— #47 largest county in Missouri, #1,667 largest county nationwide

#39. Miller County

– 2010 to 2020 population change: -26
— #1,524 among all counties nationwide
– 2010 to 2020 percent population change: -0.1%
— #39 among counties in Missouri, #1,508 among all counties nationwide
– 2020 population: 24,722
— #43 largest county in Missouri, #1,614 largest county nationwide

#38. Perry County

– 2010 to 2020 population change: -15
— #1,507 among all counties nationwide
– 2010 to 2020 percent population change: -0.1%
— #38 among counties in Missouri, #1,501 among all counties nationwide
– 2020 population: 18,956
— #57 largest county in Missouri, #1,873 largest county nationwide

#37. Daviess County

– 2010 to 2020 population change: -3
— #1,494 among all counties nationwide
– 2010 to 2020 percent population change: 0.0%
— #37 among counties in Missouri, #1,496 among all counties nationwide
– 2020 population: 8,430
— #96 largest county in Missouri, #2,542 largest county nationwide

#36. Howard County

– 2010 to 2020 population change: +7
— #1,480 among all counties nationwide
– 2010 to 2020 percent population change: +0.1%
— #36 among counties in Missouri, #1,477 among all counties nationwide
– 2020 population: 10,151
— #85 largest county in Missouri, #2,400 largest county nationwide

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#35. Ralls County

– 2010 to 2020 population change: +188
— #1,337 among all counties nationwide
– 2010 to 2020 percent population change: +1.8%
— #24 among counties in Missouri, #1,207 among all counties nationwide
– 2020 population: 10,355
— #84 largest county in Missouri, #2,386 largest county nationwide

#34. Cedar County

– 2010 to 2020 population change: +206
— #1,328 among all counties nationwide
– 2010 to 2020 percent population change: +1.5%
— #30 among counties in Missouri, #1,254 among all counties nationwide
– 2020 population: 14,188
— #72 largest county in Missouri, #2,136 largest county nationwide

#33. McDonald County

– 2010 to 2020 population change: +220
— #1,315 among all counties nationwide
– 2010 to 2020 percent population change: +1.0%
— #33 among counties in Missouri, #1,339 among all counties nationwide
– 2020 population: 23,303
— #48 largest county in Missouri, #1,670 largest county nationwide

#32. Dallas County

– 2010 to 2020 population change: +294
— #1,266 among all counties nationwide
– 2010 to 2020 percent population change: +1.8%
— #28 among counties in Missouri, #1,218 among all counties nationwide
– 2020 population: 17,071
— #63 largest county in Missouri, #1,966 largest county nationwide

#31. Ste. Genevieve County

– 2010 to 2020 population change: +334
— #1,240 among all counties nationwide
– 2010 to 2020 percent population change: +1.8%
— #26 among counties in Missouri, #1,209 among all counties nationwide
– 2020 population: 18,479
— #58 largest county in Missouri, #1,897 largest county nationwide

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#30. Benton County

– 2010 to 2020 population change: +338
— #1,235 among all counties nationwide
– 2010 to 2020 percent population change: +1.8%
— #27 among counties in Missouri, #1,217 among all counties nationwide
– 2020 population: 19,394
— #56 largest county in Missouri, #1,854 largest county nationwide

#29. Polk County

– 2010 to 2020 population change: +382
— #1,214 among all counties nationwide
– 2010 to 2020 percent population change: +1.2%
— #32 among counties in Missouri, #1,301 among all counties nationwide
– 2020 population: 31,519
— #36 largest county in Missouri, #1,384 largest county nationwide

#28. Madison County

– 2010 to 2020 population change: +400
— #1,205 among all counties nationwide
– 2010 to 2020 percent population change: +3.3%
— #17 among counties in Missouri, #1,020 among all counties nationwide
– 2020 population: 12,626
— #74 largest county in Missouri, #2,231 largest county nationwide

#27. Clinton County

– 2010 to 2020 population change: +441
— #1,180 among all counties nationwide
– 2010 to 2020 percent population change: +2.1%
— #23 among counties in Missouri, #1,161 among all counties nationwide
– 2020 population: 21,184
— #53 largest county in Missouri, #1,757 largest county nationwide

#26. Morgan County

– 2010 to 2020 population change: +441
— #1,180 among all counties nationwide
– 2010 to 2020 percent population change: +2.1%
— #22 among counties in Missouri, #1,160 among all counties nationwide
– 2020 population: 21,006
— #54 largest county in Missouri, #1,763 largest county nationwide

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#25. Laclede County

– 2010 to 2020 population change: +468
— #1,162 among all counties nationwide
– 2010 to 2020 percent population change: +1.3%
— #31 among counties in Missouri, #1,281 among all counties nationwide
– 2020 population: 36,039
— #32 largest county in Missouri, #1,279 largest county nationwide

#24. Newton County

– 2010 to 2020 population change: +534
— #1,140 among all counties nationwide
– 2010 to 2020 percent population change: +0.9%
— #34 among counties in Missouri, #1,347 among all counties nationwide
– 2020 population: 58,648
— #19 largest county in Missouri, #889 largest county nationwide

#23. Pettis County

– 2010 to 2020 population change: +779
— #1,065 among all counties nationwide
– 2010 to 2020 percent population change: +1.8%
— #25 among counties in Missouri, #1,208 among all counties nationwide
– 2020 population: 42,980
— #25 largest county in Missouri, #1,117 largest county nationwide

#22. Andrew County

– 2010 to 2020 population change: +844
— #1,047 among all counties nationwide
– 2010 to 2020 percent population change: +4.9%
— #14 among counties in Missouri, #838 among all counties nationwide
– 2020 population: 18,135
— #60 largest county in Missouri, #1,911 largest county nationwide

#21. Cole County

– 2010 to 2020 population change: +1,289
— #949 among all counties nationwide
– 2010 to 2020 percent population change: +1.7%
— #29 among counties in Missouri, #1,228 among all counties nationwide
– 2020 population: 77,279
— #16 largest county in Missouri, #726 largest county nationwide

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#20. Johnson County

– 2010 to 2020 population change: +1,418
— #920 among all counties nationwide
– 2010 to 2020 percent population change: +2.7%
— #20 among counties in Missouri, #1,095 among all counties nationwide
– 2020 population: 54,013
— #21 largest county in Missouri, #938 largest county nationwide

#19. St. Francois County

– 2010 to 2020 population change: +1,563
— #889 among all counties nationwide
– 2010 to 2020 percent population change: +2.4%
— #21 among counties in Missouri, #1,131 among all counties nationwide
– 2020 population: 66,922
— #17 largest county in Missouri, #801 largest county nationwide

#18. Pulaski County

– 2010 to 2020 population change: +1,681
— #869 among all counties nationwide
– 2010 to 2020 percent population change: +3.2%
— #18 among counties in Missouri, #1,022 among all counties nationwide
– 2020 population: 53,955
— #22 largest county in Missouri, #939 largest county nationwide

#17. Webster County

– 2010 to 2020 population change: +2,883
— #724 among all counties nationwide
– 2010 to 2020 percent population change: +8.0%
— #12 among counties in Missouri, #568 among all counties nationwide
– 2020 population: 39,085
— #29 largest county in Missouri, #1,197 largest county nationwide

#16. Warren County

– 2010 to 2020 population change: +3,019
— #702 among all counties nationwide
– 2010 to 2020 percent population change: +9.3%
— #7 among counties in Missouri, #463 among all counties nationwide
– 2020 population: 35,532
— #33 largest county in Missouri, #1,293 largest county nationwide

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#15. Franklin County

– 2010 to 2020 population change: +3,190
— #690 among all counties nationwide
– 2010 to 2020 percent population change: +3.1%
— #19 among counties in Missouri, #1,034 among all counties nationwide
– 2020 population: 104,682
— #12 largest county in Missouri, #583 largest county nationwide

#14. Taney County

– 2010 to 2020 population change: +4,391
— #599 among all counties nationwide
– 2010 to 2020 percent population change: +8.5%
— #9 among counties in Missouri, #518 among all counties nationwide
– 2020 population: 56,066
— #20 largest county in Missouri, #920 largest county nationwide

#13. St. Louis County

– 2010 to 2020 population change: +5,171
— #559 among all counties nationwide
– 2010 to 2020 percent population change: +0.5%
— #35 among counties in Missouri, #1,411 among all counties nationwide
– 2020 population: 1,004,125
— #1 largest county in Missouri, #49 largest county nationwide

#12. Jasper County

– 2010 to 2020 population change: +5,357
— #554 among all counties nationwide
– 2010 to 2020 percent population change: +4.6%
— #15 among counties in Missouri, #870 among all counties nationwide
– 2020 population: 122,761
— #9 largest county in Missouri, #518 largest county nationwide

#11. Cape Girardeau County

– 2010 to 2020 population change: +6,036
— #535 among all counties nationwide
– 2010 to 2020 percent population change: +8.0%
— #11 among counties in Missouri, #565 among all counties nationwide
– 2020 population: 81,710
— #15 largest county in Missouri, #701 largest county nationwide

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#10. Lincoln County

– 2010 to 2020 population change: +7,008
— #509 among all counties nationwide
– 2010 to 2020 percent population change: +13.3%
— #4 among counties in Missouri, #275 among all counties nationwide
– 2020 population: 59,574
— #18 largest county in Missouri, #878 largest county nationwide

#9. Jefferson County

– 2010 to 2020 population change: +8,006
— #483 among all counties nationwide
– 2010 to 2020 percent population change: +3.7%
— #16 among counties in Missouri, #967 among all counties nationwide
– 2020 population: 226,739
— #7 largest county in Missouri, #307 largest county nationwide

#8. Cass County

– 2010 to 2020 population change: +8,346
— #474 among all counties nationwide
– 2010 to 2020 percent population change: +8.4%
— #10 among counties in Missouri, #527 among all counties nationwide
– 2020 population: 107,824
— #10 largest county in Missouri, #567 largest county nationwide

#7. Christian County

– 2010 to 2020 population change: +11,420
— #400 among all counties nationwide
– 2010 to 2020 percent population change: +14.8%
— #2 among counties in Missouri, #234 among all counties nationwide
– 2020 population: 88,842
— #13 largest county in Missouri, #662 largest county nationwide

#6. Platte County

– 2010 to 2020 population change: +17,396
— #316 among all counties nationwide
– 2010 to 2020 percent population change: +19.5%
— #1 among counties in Missouri, #124 among all counties nationwide
– 2020 population: 106,718
— #11 largest county in Missouri, #574 largest county nationwide

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#5. Boone County

– 2010 to 2020 population change: +20,968
— #280 among all counties nationwide
– 2010 to 2020 percent population change: +12.9%
— #5 among counties in Missouri, #293 among all counties nationwide
– 2020 population: 183,610
— #8 largest county in Missouri, #364 largest county nationwide

#4. Greene County

– 2010 to 2020 population change: +23,741
— #259 among all counties nationwide
– 2010 to 2020 percent population change: +8.6%
— #8 among counties in Missouri, #509 among all counties nationwide
– 2020 population: 298,915
— #5 largest county in Missouri, #234 largest county nationwide

#3. Clay County

– 2010 to 2020 population change: +31,396
— #203 among all counties nationwide
– 2010 to 2020 percent population change: +14.1%
— #3 among counties in Missouri, #253 among all counties nationwide
– 2020 population: 253,335
— #6 largest county in Missouri, #276 largest county nationwide

#2. Jackson County

– 2010 to 2020 population change: +43,046
— #148 among all counties nationwide
– 2010 to 2020 percent population change: +6.4%
— #13 among counties in Missouri, #676 among all counties nationwide
– 2020 population: 717,204
— #2 largest county in Missouri, #94 largest county nationwide

#1. St. Charles County

– 2010 to 2020 population change: +44,777
— #144 among all counties nationwide
– 2010 to 2020 percent population change: +12.4%
— #6 among counties in Missouri, #307 among all counties nationwide
– 2020 population: 405,262
— #3 largest county in Missouri, #177 largest county nationwide

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