16,931 people (2024 Census estimate, −0.6% since 2020)
778 square miles of land · 22 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.
16 active community water systems list Clayton County in the area they serve, reporting 9,653 people served in all (a system that crosses county lines counts its whole population).
| GUTTENBERG WATER UTILITY groundwater · local government · IA2242018 | 1,817 served |
| MONONA MUNICIPAL WATER DEPT groundwater · local government · IA2264095 | 1,471 served |
| ELKADER MUNI WATER DEPT groundwater · local government · IA2223011 | 1,219 served |
| STRAWBERRY POINT WATER SUPPLY groundwater · local government · IA2279003 | 1,155 served |
| EDGEWOOD WATER SUPPLY groundwater · local government · IA2220002 | 939 served |
| GARNAVILLO WATER SUPPLY groundwater · local government · IA2234074 | 763 served |
| MCGREGOR WATER DEPT groundwater · local government · IA2258012 | 747 served |
| MARQUETTE WATER SUPPLY groundwater · local government · IA2256041 | 429 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 14 people were held in Clayton County's jail, in Vera's latest figure (2019), or 138 per 100,000 residents ages 15–64. In 2014 it was about 10.
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.
3 school districts have their office in Clayton County. School taxes are usually the largest part of a property tax bill.
Spent $13 million — $10.9 million to run schools, about $12,162 per student, plus $1.6 million on buildings and equipment. Money in: $5.6 million local (mostly property tax), $7.3 million state, $1.1 million federal. Long-term debt: $1.6 million.
Spent $10.1 million — $6.6 million to run schools, about $12,795 per student, plus $3.1 million on buildings and equipment. Money in: $3.7 million local (mostly property tax), $3.5 million state, $1.3 million federal. Long-term debt: $1.8 million.
Spent $7.4 million — $5.9 million to run schools, about $12,478 per student, plus $670,000 on buildings and equipment. Money in: $3.7 million local (mostly property tax), $4 million state, $589,000 federal. Long-term debt: $6.1 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 Clayton County about $14.5 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.
257 bridges in Clayton County: 78 in good condition, 141 fair, and 38 poor (14.8%). “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.
| FLEETWOOD RD over BEAR CR · built 1930 | 589 vehicles a day |
| BRIDGE ST over HONEY CREEK · built 1973 | 589 vehicles a day |
| GRANDVIEW RD over VOLGA RIVER · built 1960 | 491 vehicles a day |
| 6TH ST over DRAINAGE · built 1920 | 242 vehicles a day |
| MESQUITE RD over PECK CREEK · built 1913 | 113 vehicles a day |
| GLACIER RD over STREAM · built 1925 | 79 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $1.7 million of work in Clayton County in fiscal 2025, about $97 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 Clayton 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 Clayton County built: brayden.ozark@gmail.com.
More of Iowa: the state government and every county in Iowa.
Nearby counties: Delaware County (25 mi) · Fayette County (26 mi) · Allamakee County (30 mi) · Grant County, WI (32 mi) · Crawford County, WI (34 mi) · Dubuque County (34 mi).