25,825 people (2024 Census estimate, +0.5% since 2020)
863 square miles of land · 30 people per square mile
“Highest” and “lowest” are just order, not grades: a high rank for poverty or hazard losses means more of it. Each figure's source is in its section below.
10 active community water systems list Plymouth County in the area they serve, reporting 17,313 people served in all (a system that crosses county lines counts its whole population).
| LEMARS WATER DEPARTMENT groundwater · local government · IA7540174 | 10,606 served |
| REMSEN MUNICIPAL UTILITIES groundwater · local government · IA7568079 | 1,678 served |
| AKRON, CITY OF groundwater · local government · IA7509008 | 1,558 served |
| KINGSLEY WATER SUPPLY groundwater · local government · IA7537032 | 1,396 served |
| HINTON WATER SUPPLY groundwater · local government · IA7528051 | 935 served |
| MERRILL MUNICIPAL WATER SUPPLY groundwater · local government · IA7548072 | 717 served |
| BRUNSVILLE MUNICIPAL WATER SUPPLY buys groundwater · local government · IA7514049 | 129 served |
| WESTFIELD WATER SUPPLY groundwater · local government · IA7589008 | 123 served |
Source: U.S. EPA Safe Drinking Water Information System (SDWIS), active community systems, . Look up any system's violations and test results with EPA's search using its ID.
About 0 people were held in Plymouth County's jail, in Vera's latest figure (2021). In 2016 it was about 28.
Source: Vera Institute of Justice, Incarceration Trends (built from federal Bureau of Justice Statistics jail surveys). Counties without their own jail, or that share one, may show no figure.
5 school districts have their office in Plymouth County. School taxes are usually the largest part of a property tax bill.
Spent $29.1 million — $26.7 million to run schools, about $11,576 per student, plus $1.3 million on buildings and equipment. Money in: $13.5 million local (mostly property tax), $19.2 million state, $2.3 million federal. Long-term debt: $1.5 million.
Spent $11.1 million — $9.8 million to run schools, about $11,633 per student, plus $995,000 on buildings and equipment. Money in: $6.9 million local (mostly property tax), $4.7 million state, $543,000 federal. Long-term debt: $3.5 million.
Spent $16.7 million — $8.6 million to run schools, about $14,145 per student, plus $7.3 million on buildings and equipment. Money in: $4.8 million local (mostly property tax), $5.2 million state, $568,000 federal. Long-term debt: $8.7 million.
Spent $7.3 million — $6.2 million to run schools, about $13,704 per student, plus $567,000 on buildings and equipment. Money in: $3.4 million local (mostly property tax), $3.9 million state, $659,000 federal. Long-term debt: $3 million.
Spent $6.6 million — $4.8 million to run schools, about $15,626 per student, plus $431,000 on buildings and equipment. Money in: $3.6 million local (mostly property tax), $2.1 million state, $707,000 federal. Long-term debt: $1.3 million.
Source: U.S. Census Bureau, 2023 Annual Survey of School System Finances. Districts are listed by the county of their main office; some serve neighboring counties too.
Source: County Health Rankings & Roadmaps 2025 (University of Wisconsin Population Health Institute), which gathers federal data (CDC, Census, and others); measures cover different recent years. Blank lines aren't reported for small counties.
Overall risk: Relatively Low compared with other U.S. counties. FEMA estimates natural hazards cost Plymouth County about $17.6 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very High; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
430 bridges in Plymouth County: 233 in good condition, 107 fair, and 90 poor (20.9%). “Poor” means a main part — the deck, the beams, or the supports — is rated 4 or lower on the federal 0–9 scale. It doesn't mean unsafe to drive; unsafe bridges are closed.
| US 75 over STREAM · built 1926 | 14,000 vehicles a day |
| FM over STEPHENS CREEK · built 1960 | 628 vehicles a day |
| FM K-42 over CARTER CREEK · built 1941 | 190 vehicles a day |
| FM K-42 over CARTER CREEK · built 1966 | 190 vehicles a day |
| FM C-43 over BROKEN KETTLE CREEK · built 1960 | 159 vehicles a day |
| 150TH ST over FLOYD RIVER · built 1954 | 131 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $28 million of work in Plymouth County in fiscal 2025, about $1,090 per resident — to the county, cities, schools, hospitals, nonprofits and others.
Source: USAspending.gov, grants by place of performance, fiscal 2025 (Oct. 2024 to Sept. 2025). Search it by county to see each award.
From Grants.gov: posted grants listing county governments as eligible, soonest deadline first; research-only and overseas programs left out; list updated 2026-10-13, refreshed weekly. 62 are open in all. Cities, towns, school districts and nonprofits have their own lists there.
Registration deadlines, early voting and polling places for Iowa are on the federal site vote.gov, which links to the state's official election office.
The budget, property tax rates, audits, local officials and offices for Plymouth County come from the county's own records, which we haven't gathered — not gathered, never hidden. See what a full county site looks like, or ask to have Plymouth County built: brayden.ozark@gmail.com.
More of Iowa: the state government and every county in Iowa.
Nearby counties: Union County, SD (23 mi) · Sioux County (24 mi) · Woodbury County (25 mi) · Cherokee County (30 mi) · Dakota County, NE (30 mi) · Dixon County, NE (37 mi).