37,495 people (2024 Census estimate, −1.9% since 2020)
1,713 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.
22 active community water systems list Brown County in the area they serve, reporting 58,830 people served in all (a system that crosses county lines counts its whole population).
| ABERDEEN surface water · local government · SD4600020 | 27,989 served |
| WEB WATER DEVELOPMENT ASSOCIATION surface water · private · SD4601089 | 20,750 served |
| BROWN-DAY-MARSHALL RWS groundwater · private · SD4600882 | 5,673 served |
| GROTON buys surface water · local government · SD4600147 | 1,380 served |
| WARNER buys surface water · local government · SD4600418 | 485 served |
| LAKESIDE ESTATES buys surface water · private · SD4600022 | 460 served |
| COUNTRY VILLAGE PARK buys surface water · private · SD4600021 | 340 served |
| PRAIRIEWOOD PROPERTY OWNERS buys surface water · private · SD4602125 | 300 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 58 people were held in Brown County's jail, in Vera's latest figure (2019), or 240 per 100,000 residents ages 15–64. In 2014 it was about 31.
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.
4 school districts have their office in Brown County. School taxes are usually the largest part of a property tax bill.
Spent $58.1 million — $47.6 million to run schools, about $10,999 per student, plus $10.1 million on buildings and equipment. Money in: $28.6 million local (mostly property tax), $24.1 million state, $9.2 million federal. Long-term debt: $18.9 million.
Spent $8.2 million — $7.2 million to run schools, about $12,137 per student, plus $749,000 on buildings and equipment. Money in: $7 million local (mostly property tax), $400,000 state, $720,000 federal. Long-term debt: $6.2 million.
Spent $5.2 million — $3.4 million to run schools, about $10,685 per student, plus $1.8 million on buildings and equipment. Money in: $2.7 million local (mostly property tax), $1.9 million state, $475,000 federal. Long-term debt: $2.1 million.
Spent $3 million — $2.8 million to run schools, about $16,345 per student, plus $183,000 on buildings and equipment. Money in: $2.2 million local (mostly property tax), $724,000 state, $364,000 federal.
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 Brown County about $36.6 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.
170 bridges in Brown County: 55 in good condition, 95 fair, and 20 poor (11.8%). “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.
| US012 over MOCCASIN CK · built 1954 | 21,635 vehicles a day |
| US281 over ELM RV · built 1959 | 3,041 vehicles a day |
| 10TH AVENUE SE over MOCCASIN CREEK · built 1974 | 2,069 vehicles a day |
| 134TH STREET over CREEK · built 1930 | 1,400 vehicles a day |
| 8TH AVENUE SE over MOCCASIN CREEK · built 1976 | 500 vehicles a day |
| 396TH AVENUE over JAMES RIVER · built 1957 | 252 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $18.9 million of work in Brown County in fiscal 2025, about $493 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 South Dakota 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 Brown 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 Brown County built: brayden.ozark@gmail.com.
More of South Dakota: the state government and every county in South Dakota.
Nearby counties: Dickey County, ND (36 mi) · Marshall County (39 mi) · Day County (41 mi) · Edmunds County (43 mi) · McPherson County (44 mi) · Spink County (46 mi).