This is less than a one percent rise in Monroe County’s population, from 34,898 in 2020 to 34,932 in 2021.
Monroe County had the 40th largest population in Illinois in 2021.
The US Census Bureau found more than 73 percent of counties in the US saw a natural decrease in population in 2021. This is up from a 55.5 percent increase in 2020.
The Midwest suffered the most sustained population decreases, with many counties along the US East Coast and through the Rocky Mountains seeing increases.
The US population continues to grow, though at a slower rate than before.
Illinois Counties By Population Change from 2020 to 2021
| County | 2020 Estimated Population | 2021 Estimated Population | % Change in Population From Year to Year |
|---|---|---|---|
| Brown County | 6,217 | 6,421 | 3.3% |
| Kendall County | 132,291 | 134,867 | 1.9% |
| Johnson County | 13,307 | 13,463 | 1.2% |
| Pope County | 3,744 | 3,779 | 0.9% |
| Grundy County | 52,514 | 52,989 | 0.9% |
| Piatt County | 16,654 | 16,753 | 0.6% |
| Perry County | 20,880 | 20,985 | 0.5% |
| Hardin County | 3,634 | 3,650 | 0.4% |
| McHenry County | 309,770 | 311,122 | 0.4% |
| Logan County | 27,879 | 27,992 | 0.4% |
| Randolph County | 30,055 | 30,142 | 0.3% |
| Champaign County | 205,469 | 205,943 | 0.2% |
| Carroll County | 15,664 | 15,698 | 0.2% |
| Will County | 695,903 | 697,252 | 0.2% |
| DeKalb County | 100,233 | 100,414 | 0.2% |
| Moultrie County | 14,486 | 14,510 | 0.2% |
| Crawford County | 18,639 | 18,659 | 0.1% |
| Monroe County | 34,898 | 34,932 | 0.1% |
| Lee County | 34,021 | 34,049 | 0.1% |
| Coles County | 46,737 | 46,765 | 0.1% |
| McLean County | 170,870 | 170,889 | 0% |
| Richland County | 15,803 | 15,796 | 0% |
| Douglas County | 19,742 | 19,722 | -0.1% |
| Pike County | 14,633 | 14,618 | -0.1% |
| Kane County | 516,155 | 515,588 | -0.1% |
| Ford County | 13,533 | 13,511 | -0.2% |
| White County | 13,808 | 13,784 | -0.2% |
| Marshall County | 11,691 | 11,663 | -0.2% |
| Livingston County | 35,752 | 35,664 | -0.2% |
| Montgomery County | 28,157 | 28,084 | -0.3% |
| Lake County | 713,217 | 711,239 | -0.3% |
| Clinton County | 36,896 | 36,793 | -0.3% |
| Boone County | 53,326 | 53,159 | -0.3% |
| Williamson County | 67,094 | 66,879 | -0.3% |
| Mercer County | 15,633 | 15,582 | -0.3% |
| Fayette County | 21,460 | 21,384 | -0.4% |
| LaSalle County | 109,359 | 108,965 | -0.4% |
| Whiteside County | 55,509 | 55,305 | -0.4% |
| Madison County | 265,498 | 264,490 | -0.4% |
| Bond County | 16,663 | 16,596 | -0.4% |
| Washington County | 13,711 | 13,655 | -0.4% |
| Jefferson County | 37,029 | 36,877 | -0.4% |
| Henderson County | 6,339 | 6,312 | -0.4% |
| Jo Daviess County | 22,035 | 21,939 | -0.4% |
| Woodford County | 38,395 | 38,225 | -0.4% |
| Ogle County | 51,678 | 51,449 | -0.4% |
| Tazewell County | 131,018 | 130,413 | -0.5% |
| Schuyler County | 6,875 | 6,843 | -0.5% |
| Henry County | 49,138 | 48,907 | -0.5% |
| Franklin County | 37,636 | 37,442 | -0.5% |
| Jersey County | 21,444 | 21,333 | -0.5% |
| Shelby County | 20,900 | 20,789 | -0.5% |
| Effingham County | 34,614 | 34,430 | -0.5% |
| Lawrence County | 15,234 | 15,152 | -0.5% |
| Iroquois County | 26,984 | 26,827 | -0.6% |
| Jasper County | 9,247 | 9,193 | -0.6% |
| Morgan County | 32,798 | 32,606 | -0.6% |
| Kankakee County | 107,236 | 106,601 | -0.6% |
| Marion County | 37,613 | 37,390 | -0.6% |
| Greene County | 11,915 | 11,843 | -0.6% |
| Winnebago County | 284,858 | 283,119 | -0.6% |
| Jackson County | 52,896 | 52,565 | -0.6% |
| De Witt County | 15,441 | 15,341 | -0.6% |
| Sangamon County | 196,012 | 194,734 | -0.7% |
| DuPage County | 931,153 | 924,885 | -0.7% |
| Clark County | 15,407 | 15,300 | -0.7% |
| Christian County | 33,900 | 33,662 | -0.7% |
| Bureau County | 33,118 | 32,883 | -0.7% |
| Fulton County | 33,440 | 33,197 | -0.7% |
| St. Clair County | 256,789 | 254,796 | -0.8% |
| Cumberland County | 10,428 | 10,345 | -0.8% |
| Menard County | 12,265 | 12,164 | -0.8% |
| Hamilton County | 7,977 | 7,911 | -0.8% |
| Hancock County | 17,552 | 17,400 | -0.9% |
| Adams County | 65,530 | 64,954 | -0.9% |
| Gallatin County | 4,947 | 4,903 | -0.9% |
| Macoupin County | 44,810 | 44,406 | -0.9% |
| McDonough County | 27,079 | 26,828 | -0.9% |
| Clay County | 13,267 | 13,143 | -0.9% |
| Knox County | 49,736 | 49,268 | -0.9% |
| Rock Island County | 144,267 | 142,909 | -0.9% |
| Calhoun County | 4,411 | 4,369 | -1% |
| Wayne County | 16,121 | 15,963 | -1% |
| Stephenson County | 44,457 | 44,021 | -1% |
| Peoria County | 181,225 | 179,432 | -1% |
| Wabash County | 11,316 | 11,202 | -1% |
| Vermilion County | 73,883 | 73,095 | -1.1% |
| Mason County | 13,026 | 12,881 | -1.1% |
| Massac County | 14,125 | 13,960 | -1.2% |
| Macon County | 103,647 | 102,432 | -1.2% |
| Putnam County | 5,635 | 5,566 | -1.2% |
| Saline County | 23,634 | 23,320 | -1.3% |
| Edgar County | 16,755 | 16,520 | -1.4% |
| Cass County | 12,956 | 12,773 | -1.4% |
| Warren County | 16,777 | 16,531 | -1.5% |
| Union County | 17,179 | 16,923 | -1.5% |
| Cook County | 5,262,741 | 5,173,146 | -1.7% |
| Stark County | 5,391 | 5,294 | -1.8% |
| Scott County | 4,927 | 4,836 | -1.8% |
| Pulaski County | 5,161 | 5,065 | -1.9% |
| Edwards County | 6,205 | 6,075 | -2.1% |
| Alexander County | 5,168 | 5,030 | -2.7% |
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