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Plymouth County, IA


Designated Market Area: Sioux City, IA-NE-SD
USDA County Type (2025): Manufacturing
American Communities Project County Type (2023): Rural Middle America

Places in Plymouth County, IA     [Sort places by name]

 

Tracts in Plymouth County, IA

   



Click here to view demographic data for Plymouth County, IA

2024 population: 25,825   ( 127 from 2020)
Land area: 862.8 square miles
Population density: 29.9 persons per square mile

2024 Census data
White:22,487 87.07% 2.9%
Black:6452.50% 50.0%
Indian:1080.42% 4.4%
Asian:4231.64% 82.3%
2+ races:3171.23% 13.6%
Hispanic:1,8457.14% 24.3%
Total non-White:3,33812.93% 31.5%

2020-2024 ComponentsNumberRate
Births:1,275 12.4
Deaths:1,18211.5
Net Migration: -314-3.1
Net Immigration: 3343.2
Change in White population:-673 -2.6
Change in Non-White pop.:800 3.1



Historical Presidential Election Results for Plymouth County, IA

Recent Trends
VotesΔ MarginSwing %
2024 vs. 2020 R +169 R +559 R + 4.9%
D -390
2024 vs. 2016 R +981 R +762 R + 0.8%
D +219
2020 vs. 2016 R +812 R +203 D + 4.0%
D +609
2024 vs. 2012 R +2,064 R +3,124 R + 20.2%
D -1,060
2016 vs. 2008 R +1,915 R +3,659 R + 28.8%
D -1,744
How to interpret this table


Click on the Year to view county-level data for that election.

YearTurnout WinnerRunner-Up OtherTotal Votes Diff
(St) 		Diff
(US) 		PSV
2024 72% Donald Trump (R) 10,661 76.3% Kamala Harris (D) 3,104 22.2% 206 [+] 1.5% 13,971 21 27 0.84%
2020 74% Donald Trump* (R) 10,492 73.9% Joe Biden (D) 3,494 24.6% 202 [+] 1.4% 14,188 21 27 0.84%
2016 70% Donald Trump (R) 9,680 73.4% Hillary Clinton (D) 2,885 21.9% 625 [+] 4.7% 13,190 22 27 0.84%
2012 69% Mitt Romney (R) 8,597 66.4% Barack Obama* (D) 4,164 32.2% 189 [+] 1.5% 12,950 20 19 0.82%
2008 68% John McCain (R) 7,765 62.0% Barack Obama (D) 4,629 37.0% 121 [+] 1.0% 12,515 18 16 0.81%
2004 68% George W. Bush* (R) 7,810 63.9% John Kerry (D) 4,278 35.0% 134 [+] 1.1% 12,222 14 13 0.81%
2000 57% George W. Bush (R) 6,189 61.2% Albert Gore, Jr. (D) 3,499 34.6% 430 [+] 4.2% 10,118 13 13 0.77%
1996 57% Robert Dole (R) 5,117 51.4% Bill Clinton* (D) 3,745 37.6% 1,094 [+] 11.0% 9,956 11 11 0.81%
1992 62% George Bush* (R) 5,196 49.6% Bill Clinton (D) 3,171 30.2% 2,117 [+] 20.2% 10,484 12 12 0.77%
1988 57% George Bush (R) 5,316 55.3% Michael Dukakis (D) 4,220 43.9% 71 [+] 0.7% 9,607 11 2 0.78%
1984 59% Ronald Reagan* (R) 6,482 64.6% Walter Mondale (D) 3,464 34.5% 81 0.8% 10,027 11 6 0.76%
1980 60% Ronald Reagan (R) 6,515 63.0% Jimmy Carter* (D) 2,965 28.7% 866 [+] 8.4% 10,346 12 12 0.79%
1976 62% Gerald Ford* (R) 5,590 55.8% Jimmy Carter (D) 4,284 42.8% 142 [+] 1.4% 10,016 6 8 0.78%
1972 66% Richard Nixon* (R) 6,339 60.6% George McGovern (D) 4,033 38.5% 94 [+] 0.9% 10,466 3 0 0.85%
1968 71% Richard Nixon (R) 6,236 62.1% Hubert Humphrey (D) 3,234 32.2% 567 [+] 5.6% 10,037 9 19 0.86%
1964 75% Lyndon Johnson* (D) 5,691 53.6% Barry Goldwater (R) 4,920 46.4% 2 0.0% 10,613 8 8 0.90%
1960 79% Richard Nixon (R) 6,432 57.9% John Kennedy (D) 4,671 42.1% 0 0.0% 11,103 1 8 0.87%
1956 73% Dwight Eisenhower* (R) 7,246 67.4% Adlai Stevenson (D) 3,502 32.6% 0 0.0% 10,748 8 10 0.87%
1952 75% Dwight Eisenhower (R) 8,140 74.3% Adlai Stevenson (D) 2,768 25.3% 49 0.4% 10,957 11 19 0.86%
1948 65% Thomas Dewey (R) 5,002 53.1% Harry Truman* (D) 4,339 46.1% 75 [+] 0.8% 9,416 6 8 0.91%
1944 62% Thomas Dewey (R) 6,085 67.0% Franklin Roosevelt* (D) 2,970 32.7% 21 0.2% 9,076 15 21 0.86%
1940 79% Wendell Willkie (R) 7,725 66.7% Franklin Roosevelt* (D) 3,831 33.1% 23 0.2% 11,579 15 22 0.95%
1936 81% Franklin Roosevelt* (D) 5,994 52.4% Alf Landon (R) 4,133 36.1% 1,318 [+] 11.5% 11,445 -7 0 1.00%
1932 74% Franklin Roosevelt (D) 7,565 71.6% Herbert Hoover* (R) 2,888 27.3% 110 [+] 1.0% 10,563 -13 -12 1.02%
1928 71% Al Smith (D) 5,015 50.8% Herbert Hoover (R) 4,848 49.2% 0 0.0% 9,863 -13 -9 0.98%
1924 66% Calvin Coolidge (R) 3,803 42.1% Robert LaFollette (Prog) 3,628 40.2% 1,605 [+] 17.8% 9,036 -13 -12 0.93%
1920 59% Warren Harding (R) 6,090 76.2% James Cox (D) 1,801 22.5% 105 [+] 1.3% 7,996 5 16 0.89%
1916 38% Charles Evans Hughes (R) 2,666 53.1% Woodrow Wilson* (D) 2,258 45.0% 93 [+] 1.9% 5,017 -1 7 0.97%
1912 38% Woodrow Wilson (D) 2,038 41.2% Theodore Roosevelt (Prog) 2,005 40.6% 899 [+] 18.2% 4,942 -8 -7 1.00%
1908 40% William Taft (R) 2,622 53.2% William J. Bryan (D) 2,168 44.0% 140 [+] 2.8% 4,930 -2 2 1.00%
1904 39% Theodore Roosevelt (R) 2,905 61.5% Alton Parker (D) 1,663 35.2% 158 [+] 3.3% 4,726 -2 5 0.97%
1900 43% William McKinley* (R) 2,712 53.0% William J. Bryan (D) 2,307 45.1% 95 [+] 1.9% 5,114 -5 1 0.96%
* incumbent         PSV: percent of state vote

Historical Statewide Election Results for Plymouth County, IA

Click on the Year to view county-level data for that election.

YearTypeTurnout WinnerRunner-Up OtherTotal VotesDiff PSV
2022 S3 50% Charles Grassley* (R) 7,650 78.7% Michael Franken (D) 2,053 21.1% 13 [+] 0.1% 9,716 23 0.80%
2022 G 51% Kim Reynolds* (R) 8,027 81.7% Deidre DeJear (D) 1,643 16.7% 153 [+] 1.6% 9,823 24 0.80%
2020 S2 73% Joni Ernst* (R) 10,145 72.3% Theresa Greenfield (D) 3,587 25.6% 307 [+] 2.2% 14,039 21 0.84%
2018 G 57% Kim Reynolds* (R) 7,941 73.3% Fred Hubbell (D) 2,717 25.1% 171 [+] 1.6% 10,829 23 0.82%
2016 S3 68% Charles Grassley* (R) 10,338 79.7% Patty Judge (D) 2,300 17.7% 332 [+] 2.6% 12,970 20 0.84%
2014 S2 49% Joni Ernst (R) 6,678 72.6% Bruce Braley (D) 2,182 23.7% 342 [+] 3.7% 9,202 20 0.81%
2014 G 49% Terry Branstad* (R) 7,366 79.8% Jack Hatch (D) 1,695 18.4% 164 [+] 1.8% 9,225 21 0.82%
2010 S3 48% Charles Grassley* (R) 7,219 82.1% Roxanne Conlin (D) 1,422 16.2% 150 [+] 1.7% 8,791 18 0.79%
2010 G 48% Terry Branstad (R) 6,452 73.1% Chet Culver* (D) 2,139 24.2% 236 [+] 2.7% 8,827 20 0.79%
2008 S2 66% Tom Harkin* (D) 6,240 51.5% Christopher Reed (R) 5,886 48.5% 0 0.0% 12,126 11 0.81%
2006 G 45% Jim Nussle (R) 5,275 64.9% Chet Culver (D) 2,775 34.1% 81 [+] 1.0% 8,131 20 0.77%
2004 S3 66% Charles Grassley* (R) 9,588 80.1% Art Small (D) 2,229 18.6% 158 [+] 1.3% 11,975 10 0.81%
2002 S2 42% Greg Ganske (R) 3,990 53.4% Tom Harkin* (D) 3,307 44.2% 178 [+] 2.4% 7,475 10 0.73%
2002 G 42% Doug Gross (R) 4,062 53.9% Tom Vilsack* (D) 3,264 43.3% 214 [+] 2.8% 7,540 9 0.74%
1998 S3 38% Charles Grassley* (R) 5,461 81.2% David Osterberg (D) 1,245 18.5% 20 [+] 0.3% 6,726 13 0.71%
1998 G 39% Jim Ross Lightfoot (R) 4,369 63.4% Tom Vilsack (D) 2,482 36.0% 40 [+] 0.6% 6,891 17 0.72%
1996 S2 55% Jim Ross Lightfoot (R) 6,099 63.4% Tom Harkin* (D) 3,366 35.0% 155 [+] 1.6% 9,620 17 0.79%
1994 G 43% Terry Branstad* (R) 4,964 66.9% Bonnie Campbell (D) 2,368 31.9% 85 [+] 1.1% 7,417 10 0.74%
1992 S3 52% Charles Grassley* (R) 6,969 78.6% Jean Lloyd-Jones (D) 1,570 17.7% 325 [+] 3.7% 8,864 9 0.69%
1990 S2 43% Tom Tauke (R) 4,100 56.8% Tom Harkin* (D) 3,106 43.1% 6 [+] 0.1% 7,212 11 0.73%
1990 G 44% Terry Branstad* (R) 5,087 70.0% Donald Avenson (D) 2,160 29.7% 24 [+] 0.3% 7,271 9 0.74%
1986 S3 45% Charles Grassley* (R) 5,366 71.0% John Roehrick (D) 2,168 28.7% 21 [+] 0.3% 7,555 5 0.85%
1986 G 47% Terry Branstad* (R) 4,866 61.4% Lowell Junkins (D) 3,056 38.6% 0 0.0% 7,922 10 0.87%
1984 S2 57% Roger Jepsen* (R) 4,905 50.9% Tom Harkin (D) 4,667 48.4% 71 [+] 0.7% 9,643 7 0.75%
1982 G 43% Terry Branstad (R) 4,780 65.1% Roxanne Conlin (D) 2,541 34.6% 27 [+] 0.4% 7,348 12 0.71%
1980 S3 56% Charles Grassley (R) 6,358 65.4% John Culver* (D) 3,243 33.4% 114 [+] 1.2% 9,715 12 0.76%
1978 S2 42% Roger Jepsen (R) 4,218 62.7% Dick Clark* (D) 2,485 36.9% 26 [+] 0.4% 6,729 12 0.82%
1978 G 42% Robert Ray* (R) 4,310 63.0% Jerry Fitzgerald (D) 2,506 36.6% 28 [+] 0.4% 6,844 5 0.81%
1974 S3 46% David Stanley (R) 3,962 53.5% John Culver (D) 3,420 46.2% 25 [+] 0.3% 7,407 6 0.83%
1974 G 48% Robert Ray* (R) 4,499 57.9% James Schaben (D) 3,213 41.4% 58 [+] 0.7% 7,770 0 0.84%
1972 S2 65% Dick Clark (D) 5,597 54.4% Jack Miller* (R) 4,667 45.3% 32 [+] 0.3% 10,296 1 0.86%
1972 G 65% Robert Ray* (R) 6,164 59.8% Paul Franzenburg (D) 4,097 39.8% 43 [+] 0.4% 10,304 1 0.85%
1970 G 41% Robert Ray* (R) 3,266 54.2% Robert Fulton (D) 2,702 44.8% 58 [+] 1.0% 6,026 3 0.76%
1968 S3 70% David Stanley (R) 5,577 56.2% Harold Hughes (D) 4,340 43.8% 3 [+] 0.0% 9,920 7 0.87%
1968 G 68% Robert Ray (R) 5,802 60.0% Paul Franzenburg (D) 3,866 40.0% 0 0.0% 9,668 6 0.85%
1966 S2 55% Jack Miller* (R) 5,607 72.2% E.B. Smith (D) 2,116 27.2% 43 [+] 0.6% 7,766 11 0.91%
1966 G 56% William Murray (R) 4,089 51.4% Harold Hughes* (D) 3,851 48.4% 22 [+] 0.3% 7,962 7 0.89%
1964 G 74% Harold Hughes* (D) 6,556 63.0% Evan Hultman (R) 3,818 36.7% 27 [+] 0.3% 10,401 5 0.89%
1962 S3 49% Bourke Hickenlooper* (R) 4,097 59.0% E.B. Smith (D) 2,849 41.0% 0 0.0% 6,946 6 0.86%
1962 G 51% Norman Erbe* (R) 3,900 54.9% Harold Hughes (D) 3,200 45.1% 0 0.0% 7,100 7 0.87%
1960 S2 77% Jack Miller (R) 6,189 57.4% Herschel Loveless (D) 4,585 42.6% 0 0.0% 10,774 6 0.87%
1960 G 76% Norman Erbe (R) 5,962 56.1% Edward McManus (D) 4,659 43.9% 0 0.0% 10,621 4 0.86%
*: incumbent               +: ran on additional party lines               Type: G: Governor; S1,S2,S3: Senate Class 1, 2 or 3
italics: special election           RO: runoff election           PSV: percent of state vote


Historical U.S. House Election Results for Plymouth County, IA

Click on the District to view county-level data for that election (where available).

DateDistrictWinnerRunner-Up OtherTotal Votes
2024-11-05 IA04Randy Feenstra* (R) 10,373 78.4% Ryan Melton (D) 2,810 21.2% 50 0.4% 13,233
County Total for 2024-11-05:   13,233
2022-11-08 IA04Randy Feenstra* (R) 7,734 80.2% Ryan Melton (D) 1,770 18.4% 141 1.5% 9,645
County Total for 2022-11-08:   9,645
2020-11-03 IA04Randy Feenstra (R) 10,126 73.5% J.D. Scholten (D) 3,620 26.3% 31 0.2% 13,777
County Total for 2020-11-03:   13,777
2018-11-06 IA04Steve King* (R) 6,503 60.3% J.D. Scholten (D) 4,084 37.9% 197 1.8% 10,784
County Total for 2018-11-06:   10,784
2016-11-08 IA04Steve King* (R) 9,207 71.9% Kim Weaver (D) 3,575 27.9% 18 0.1% 12,800
County Total for 2016-11-08:   12,800
2014-11-04 IA04Steve King* (R) 6,590 71.6% Jim Mowrer (D) 2,608 28.3% 5 0.1% 9,203
County Total for 2014-11-04:   9,203
2012-11-06 IA04Steve King* (R) 8,615 67.4% Christie Vilsack (D) 3,973 31.1% 186 1.5% 12,774
County Total for 2012-11-06:   12,774
2010-11-02 IA05Steve King* (R) 6,347 72.6% Matthew Campbell (D) 2,270 26.0% 122 1.4% 8,739
County Total for 2010-11-02:   8,739
2008-11-04 IA05Steve King* (R) 7,907 66.0% Rob Hubler (D) 3,808 31.8% 262 2.2% 11,977
County Total for 2008-11-04:   11,977
2006-11-07 IA05Steve King* (R) 5,445 67.6% Joyce Schulte (D) 2,114 26.2% 501 6.2% 8,060
County Total for 2006-11-07:   8,060
2004-11-02 IA05Steve King* (R) 7,928 68.0% Joyce Schulte (D) 3,728 32.0% 3 0.0% 11,659
County Total for 2004-11-02:   11,659
2002-11-05 IA05Steve King (R) 4,871 66.8% Paul Shomshor (D) 2,419 33.2% 6 0.1% 7,296
County Total for 2002-11-05:   7,296
2000-11-07 IA05Tom Latham* (R) 7,177 73.5% Mike Palecek (D) 2,409 24.7% 173 1.8% 9,759
County Total for 2000-11-07:   9,759
1998-11-03 IA05Tom Latham* (R) 4,834 100.0% 0 0.0% 4,834
County Total for 1998-11-03:   4,834
1996-11-05 IA05Tom Latham* (R) 6,519 72.5% MacDonald Smith (D) 2,431 27.0% 43 0.5% 8,993
County Total for 1996-11-05:   8,993
1994-11-08 IA05Tom Latham (R) 4,574 66.5% Sheila McGuire (D) 2,306 33.5% 0 0.0% 6,880
County Total for 1994-11-08:   6,880
1992-11-03 IA05Fred Grandy* (R) 7,989 100.0% 0 0.0% 7,989
County Total for 1992-11-03:   7,989
*: incumbent           sp: special election           RO: runoff election

Voter Registration Data for Plymouth County, IA

YearTotalRepublicanDemocratOtherR/D EdgeR/D Edge %VAPOP %
2024 14,070 8,184 58.2% 2,120 15.1% 3,766 26.8% Rep +6,064 Rep +43.1% 73%
2022 15,818 8,682 54.9% 2,684 17.0% 4,452 28.1% Rep +5,998 Rep +37.9% 82%
2020 17,398 9,102 52.3% 3,195 18.4% 5,101 29.3% Rep +5,907 Rep +34.0% 90%
2018 16,942 8,401 49.6% 3,033 17.9% 5,508 32.5% Rep +5,368 Rep +31.7% 88%
2016 16,847 8,332 49.5% 3,088 18.3% 5,427 32.2% Rep +5,244 Rep +31.1% 89%
2014 16,394 7,755 47.3% 3,125 19.1% 5,514 33.6% Rep +4,630 Rep +28.2% 87%
2012 17,135 7,963 46.5% 3,381 19.7% 5,791 33.8% Rep +4,582 Rep +26.7% 92%
2010 17,089 7,520 44.0% 3,548 20.8% 6,021 35.2% Rep +3,972 Rep +23.2% 92%
2008 16,986 7,206 42.4% 3,606 21.2% 6,174 36.3% Rep +3,600 Rep +21.2% 92%
2006 16,428 7,167 43.6% 3,088 18.8% 6,173 37.6% Rep +4,079 Rep +24.8% 90%
2004 16,747 7,403 44.2% 3,054 18.2% 6,290 37.6% Rep +4,349 Rep +26.0% 93%
2002 15,290 6,738 44.1% 2,786 18.2% 5,766 37.7% Rep +3,952 Rep +25.8% 85%
2000 15,408 6,836 44.4% 2,873 18.6% 5,699 37.0% Rep +3,963 Rep +25.7% 86%
1994 12,196 5,876 48.2% 2,945 24.1% 3,375 27.7% Rep +2,931 Rep +24.0% 71%
1986 12,428 5,104 41.1% 3,314 26.7% 4,010 32.3% Rep +1,790 Rep +14.4% 74%
VAPOP% is the estimated percentage of voting age population that is registered.
Registration data may include "inactive" voters.   Data for each year pertains to the November elections.