4,395 people (2024 Census estimate, +2.3% since 2020)
838 square miles of land · 5 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.
9 active community water systems list Marshall County in the area they serve, reporting 28,557 people served in all (a system that crosses county lines counts its whole population).
| WEB WATER DEVELOPMENT ASSOCIATION surface water · private · SD4601089 | 20,750 served |
| BROWN-DAY-MARSHALL RWS groundwater · private · SD4600882 | 5,673 served |
| BRITTON buys groundwater · local government · SD4600388 | 1,215 served |
| VEBLEN buys groundwater · local government · SD4600341 | 317 served |
| LANGFORD buys groundwater · local government · SD4600189 | 283 served |
| SUNSET COLONY groundwater · private · SD4602025 | 140 served |
| EDEN buys surface water · local government · SD4600113 | 94 served |
| LAKE CITY buys groundwater · local government · SD4600186 | 45 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 3 people were held in Marshall County's jail, in Vera's latest figure (2019), or 119 per 100,000 residents ages 15–64. In 2014 it was about 3.
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 Marshall County. School taxes are usually the largest part of a property tax bill.
Spent $6.3 million — $5.4 million to run schools, about $11,349 per student, plus $825,000 on buildings and equipment. Money in: $4.9 million local (mostly property tax), $1.3 million state, $927,000 federal. Long-term debt: $5.3 million.
Spent $4 million — $3.5 million to run schools, about $14,401 per student, plus $469,000 on buildings and equipment. Money in: $2.4 million local (mostly property tax), $903,000 state, $338,000 federal. Long-term debt: $2.5 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 Marshall County about $6 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Moderate; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
38 bridges in Marshall County: 7 in good condition, 18 fair, and 13 poor (34.2%). “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.
| 415TH AVENUE over CROW CREEK DITCH · built 1974 | 322 vehicles a day |
| 100TH STREET over WILD RICE CREEK · built 1935 | 80 vehicles a day |
| 425TH AVENUE over CROW CREEK · built 1940 | 51 vehicles a day |
| 418TH AVENUE over SPAIN & LANGFORD DITCH · built 1979 | 50 vehicles a day |
| 416TH AVENUE over CROW CREEK DITCH · built 1935 | 35 vehicles a day |
| 113TH STREET over SPAIN DITCH · built 1935 | 35 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $4.5 million of work in Marshall County in fiscal 2025, about $1,042 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 Marshall 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 Marshall County built: brayden.ozark@gmail.com.
More of South Dakota: the state government and every county in South Dakota.
Nearby counties: Sargent County, ND (26 mi) · Day County (26 mi) · Roberts County (31 mi) · Brown County (39 mi) · Richland County, ND (48 mi) · Ransom County, ND (49 mi).