Iowa Counties by Population (2026)

by Kristen Carney

Updated: February 9, 2026

The most populous counties in Iowa are Polk County with 503,175, Linn County at 230,004, Scott County with 174,608, Johnson County at 156,639, and Black Hawk County with 131,049. You can get the most current Census population data for all 99 Iowa counties, sorted from the most populous counties in Iowa to the least, according to the 2024 American Community Survey.

Sure, you can copy this list right into your favorite spreadsheet tool. Or save yourself formatting headaches and grab the latest Iowa counties population data as a ready-to-use Excel™ file below. It's time to stop searching and start digging into data!

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Rank County Population
1 Polk County 503,175
2 Linn County 230,004
3 Scott County 174,608
4 Johnson County 156,639
5 Black Hawk County 131,049
6 Dallas County 107,968
7 Woodbury County 106,247
8 Story County 100,466
9 Dubuque County 99,030
10 Pottawattamie County 93,424
11 Warren County 54,409
12 Clinton County 46,268
13 Cerro Gordo County 42,632
14 Muscatine County 42,559
15 Marshall County 40,114
16 Des Moines County 38,487
17 Jasper County 37,954
18 Webster County 36,886
19 Sioux County 36,212
20 Wapello County 35,362
21 Marion County 33,642
22 Lee County 32,893
23 Boone County 26,668
24 Plymouth County 25,747
25 Benton County 25,724
26 Bremer County 25,204
27 Washington County 22,561
28 Mahaska County 22,021
29 Jones County 20,896
30 Buena Vista County 20,753
31 Buchanan County 20,694
32 Carroll County 20,594
33 Henry County 20,004
34 Winneshiek County 19,873
35 Jackson County 19,390
36 Fayette County 19,288
37 Poweshiek County 18,545
38 Cedar County 18,349
39 Dickinson County 17,990
40 Delaware County 17,558
41 Clayton County 17,013
42 Madison County 16,926
43 Tama County 16,868
44 Hardin County 16,639
45 Iowa County 16,507
46 Clay County 16,461
47 Crawford County 16,277
48 Jefferson County 15,705
49 Floyd County 15,328
50 Page County 15,131
51 Hamilton County 14,886
52 Harrison County 14,632
53 Mills County 14,568
54 Kossuth County 14,516
55 Butler County 14,268
56 O'Brien County 14,126
57 Allamakee County 14,092
58 Cass County 13,096
59 Wright County 12,791
60 Grundy County 12,384
61 Appanoose County 12,184
62 Lyon County 12,162
63 Union County 11,993
64 Chickasaw County 11,807
65 Shelby County 11,778
66 Cherokee County 11,600
67 Guthrie County 10,688
68 Louisa County 10,678
69 Hancock County 10,671
70 Winnebago County 10,583
71 Mitchell County 10,575
72 Montgomery County 10,214
73 Franklin County 9,956
74 Keokuk County 9,924
75 Calhoun County 9,803
76 Sac County 9,689
77 Clarke County 9,662
78 Humboldt County 9,591
79 Howard County 9,445
80 Emmet County 9,262
81 Davis County 9,157
82 Palo Alto County 8,863
83 Lucas County 8,716
84 Greene County 8,688
85 Monona County 8,557
86 Decatur County 7,759
87 Monroe County 7,513
88 Adair County 7,460
89 Worth County 7,350
90 Van Buren County 7,241
91 Pocahontas County 7,046
92 Ida County 6,911
93 Wayne County 6,532
94 Fremont County 6,514
95 Osceola County 6,100
96 Taylor County 5,868
97 Audubon County 5,599
98 Ringgold County 4,645
99 Adams County 3,622

United States Census Bureau. B01001 SEX BY AGE, 2024 American Community Survey 5-Year Estimates. U.S. Census Bureau, American Community Survey Office. Web. January 29, 2026. http://www.census.gov/.

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