Population
|
County
|
490,161
|
Polk
|
226,706
|
Linn
|
172,943
|
Scott
|
151,140
|
Johnson
|
131,228
|
Black Hawk
|
103,107
|
Woodbury
|
97,311
|
Dubuque
|
97,117
|
Story
|
93,453
|
Dallas
|
93,206
|
Pottawattamie
|
51,466
|
Warren
|
46,429
|
Clinton
|
42,664
|
Muscatine
|
42,450
|
Cerro Gordo
|
39,369
|
Marshall
|
38,967
|
Des Moines
|
37,185
|
Jasper
|
35,904
|
Webster
|
34,969
|
Wapello
|
34,827
|
Sioux
|
33,657
|
Lee
|
33,253
|
Marion
|
26,234
|
Boone
|
25,645
|
Benton
|
25,068
|
Plymouth
|
25,062
|
Bremer
|
22,095
|
Mahaska
|
21,965
|
Washington
|
21,118
|
Buchanan
|
20,681
|
Jones
|
20,262
|
Winneshiek
|
20,165
|
Carroll
|
19,941
|
Henry
|
|
Population
|
County
|
19,803
|
Fayette
|
19,620
|
Buena Vista
|
19,401
|
Jackson
|
18,457
|
Cedar
|
18,388
|
Poweshiek
|
18,295
|
Jefferson
|
17,625
|
Clayton
|
17,258
|
Dickinson
|
17,183
|
Delaware
|
17,061
|
Hardin
|
17,034
|
Crawford
|
17,032
|
Tama
|
16,338
|
Madison
|
16,189
|
Iowa
|
16,016
|
Clay
|
15,786
|
Floyd
|
15,268
|
Page
|
15,109
|
Mills
|
14,997
|
Hamilton
|
14,978
|
Kossuth
|
14,628
|
Butler
|
14,049
|
Harrison
|
13,835
|
O'Brien
|
13,813
|
Allamakee
|
13,091
|
Cass
|
12,739
|
Wright
|
12,452
|
Appanoose
|
12,358
|
Union
|
12,232
|
Grundy
|
12,026
|
Chickasaw
|
11,776
|
Lyon
|
11,606
|
Shelby
|
11,343
|
Cherokee
|
|
Population
|
County
|
11,178
|
Louisa
|
10,802
|
Hancock
|
10,689
|
Guthrie
|
10,608
|
Mitchell
|
10,534
|
Winnebago
|
10,188
|
Keokuk
|
10,162
|
Franklin
|
10,053
|
Montgomery
|
9,802
|
Sac
|
9,744
|
Calhoun
|
9,554
|
Humboldt
|
9,438
|
Emmet
|
9,360
|
Clarke
|
9,226
|
Howard
|
9,003
|
Palo Alto
|
8,950
|
Greene
|
8,920
|
Davis
|
8,730
|
Monona
|
8,583
|
Lucas
|
7,979
|
Decatur
|
7,807
|
Monroe
|
7,381
|
Worth
|
7,150
|
Van Buren
|
7,085
|
Adair
|
6,946
|
Fremont
|
6,901
|
Ida
|
6,797
|
Pocahontas
|
6,429
|
Wayne
|
6,167
|
Taylor
|
6,052
|
Osceola
|
5,571
|
Audubon
|
4,964
|
Ringgold
|
3,670
|
Adams
|
|