Iowa Counties by Population (2025)

by Kristen Carney Kristen Carney

Updated: August 7, 2025

The most populous counties in Iowa are Polk County with 516,185, Linn County at 231,762, Scott County with 175,601, Johnson County at 160,080, and Black Hawk County with 132,348. 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 Population Estimates Program.

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!

Download the newest population data for Iowa counties

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Rank County Population
1 Polk County 516,185
2 Linn County 231,762
3 Scott County 175,601
4 Johnson County 160,080
5 Black Hawk County 132,348
6 Dallas County 115,343
7 Woodbury County 107,257
8 Story County 102,498
9 Dubuque County 99,242
10 Pottawattamie County 93,529
11 Warren County 56,343
12 Clinton County 46,015
13 Cerro Gordo County 42,493
14 Muscatine County 42,132
15 Marshall County 40,392
16 Des Moines County 38,411
17 Jasper County 38,107
18 Webster County 36,909
19 Sioux County 36,554
20 Wapello County 35,681
21 Marion County 34,048
22 Lee County 32,376
23 Boone County 26,729
24 Plymouth County 25,825
25 Benton County 25,799
26 Bremer County 25,328
27 Washington County 22,631
28 Mahaska County 22,034
29 Jones County 21,116
30 Buena Vista County 20,816
31 Buchanan County 20,733
32 Carroll County 20,407
33 Winneshiek County 19,723
34 Jackson County 19,390
35 Henry County 19,361
36 Fayette County 19,152
37 Poweshiek County 18,454
38 Cedar County 18,231
39 Dickinson County 18,158
40 Delaware County 17,609
41 Madison County 17,161
42 Clayton County 16,931
43 Tama County 16,738
44 Clay County 16,474
45 Hardin County 16,464
46 Iowa County 16,423
47 Crawford County 16,378
48 Jefferson County 15,781
49 Page County 15,038
50 Floyd County 15,008
51 Hamilton County 14,856
52 Mills County 14,717
53 Harrison County 14,626
54 Kossuth County 14,408
55 O'Brien County 14,260
56 Allamakee County 14,184
57 Butler County 14,156
58 Cass County 13,024
59 Wright County 12,729
60 Grundy County 12,405
61 Lyon County 12,378
62 Appanoose County 12,106
63 Union County 11,955
64 Shelby County 11,821
65 Chickasaw County 11,719
66 Cherokee County 11,658
67 Guthrie County 10,774
68 Mitchell County 10,632
69 Louisa County 10,630
70 Hancock County 10,616
71 Winnebago County 10,383
72 Montgomery County 10,063
73 Franklin County 10,024
74 Keokuk County 9,855
75 Calhoun County 9,711
76 Humboldt County 9,617
77 Sac County 9,533
78 Clarke County 9,524
79 Howard County 9,360
80 Davis County 9,193
81 Emmet County 9,162
82 Palo Alto County 8,809
83 Lucas County 8,758
84 Greene County 8,662
85 Monona County 8,429
86 Decatur County 7,656
87 Adair County 7,431
88 Monroe County 7,373
89 Worth County 7,307
90 Van Buren County 7,217
91 Pocahontas County 7,006
92 Ida County 6,810
93 Wayne County 6,622
94 Fremont County 6,494
95 Osceola County 6,036
96 Taylor County 5,825
97 Audubon County 5,562
98 Ringgold County 4,608
99 Adams County 3,606

United States Census Bureau. Annual Estimates of the Resident Population: April 1, 2020 to July 1, 2024. Population Division. May 2025.

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