22,034 people (2024 Census estimate, −0.6% since 2020)
571 square miles of land · 39 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.
4 active community water systems list Mahaska County in the area they serve, reporting 25,666 people served in all (a system that crosses county lines counts its whole population).
| OSKALOOSA MUNICIPAL WATER DEPT groundwater (surface-influenced) · local government · IA6273005 | 12,808 served |
| MAHASKA RURAL WATER SYSTEM, INC. groundwater · private · IA6273901 | 11,325 served |
| MAHASKA RURAL WATER (NEW SHARON) groundwater · local government · IA6264063 | 1,368 served |
| OAK CREEK MHP buys groundwater · private · IA6273601 | 165 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 28 people were held in Mahaska County's jail, in Vera's latest figure (2019), or 204 per 100,000 residents ages 15–64. In 2014 it was about 24.
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.
2 school districts have their office in Mahaska County. School taxes are usually the largest part of a property tax bill.
Spent $37.9 million — $28.3 million to run schools, about $13,366 per student, plus $6.8 million on buildings and equipment. Money in: $11.5 million local (mostly property tax), $20.3 million state, $4 million federal. Long-term debt: $11.6 million.
Spent $9.5 million — $7.3 million to run schools, about $11,807 per student, plus $1.3 million on buildings and equipment. Money in: $5.8 million local (mostly property tax), $4.1 million state, $565,000 federal. Long-term debt: $14.4 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: Very Low compared with other U.S. counties. FEMA estimates natural hazards cost Mahaska County about $11.1 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively High; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
221 bridges in Mahaska County: 65 in good condition, 89 fair, and 67 poor (30.3%). “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.
| OLD IA 102 over BUCKLEY CREEK · built 1967 | 2,340 vehicles a day |
| FM over CEDAR CREEK · built 1963 | 470 vehicles a day |
| FM over S SKUNK RIVER · built 1967 | 430 vehicles a day |
| FM over N SKUNK RIVER · built 1966 | 370 vehicles a day |
| FM over N SKUNK RIVER OVERFLOW · built 1961 | 370 vehicles a day |
| FM over OVER UP RR · built 1961 | 370 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $17.9 million of work in Mahaska County in fiscal 2025, about $807 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 Mahaska 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 Mahaska County built: brayden.ozark@gmail.com.
More of Iowa: the state government and every county in Iowa.
Nearby counties: Marion County (24 mi) · Wapello County (24 mi) · Monroe County (24 mi) · Keokuk County (24 mi) · Poweshiek County (25 mi) · Jasper County (33 mi).