3,974 people (2024 Census estimate, +3.2% since 2020)
958 square miles of land · 4 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.
8 active community water systems list Clark County in the area they serve, reporting 8,353 people served in all (a system that crosses county lines counts its whole population).
| SIOUX RURAL WATER SYSTEM groundwater · private · SD4600866 | 4,280 served |
| CLARK RURAL WATER SYSTEM groundwater · private · SD4600881 | 2,325 served |
| CLARK buys groundwater · local government · SD4600091 | 1,148 served |
| WILLOW LAKE buys groundwater · local government · SD4600370 | 255 served |
| FORDHAM COLONY groundwater · private · SD4602064 | 142 served |
| COLLINS COLONY groundwater · private · SD4602358 | 95 served |
| SHAMROCK COLONY groundwater · private · SD4602267 | 75 served |
| GARDEN CITY buys groundwater · local government · SD4600137 | 33 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 7 people were held in Clark County's jail, in Vera's latest figure (2021), or 365 per 100,000 residents ages 15–64. In 2016 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 Clark County. School taxes are usually the largest part of a property tax bill.
Spent $6.1 million — $5.6 million to run schools, about $11,674 per student, plus $411,000 on buildings and equipment. Money in: $4 million local (mostly property tax), $1.6 million state, $1.2 million federal. Long-term debt: $71,000.
Spent $5.6 million — $3.7 million to run schools, about $11,529 per student, plus $1.6 million on buildings and equipment. Money in: $2.9 million local (mostly property tax), $1.2 million state, $387,000 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 Clark County about $4.2 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively High; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
21 bridges in Clark County: 11 in good condition, 9 fair, and 1 poor (4.8%). “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.
| 419TH AVENUE over CREEK · built 1983 | 39 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $11 million of work in Clark County in fiscal 2025, about $2,878 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 Clark 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 Clark County built: brayden.ozark@gmail.com.
More of South Dakota: the state government and every county in South Dakota.
Nearby counties: Codington County (27 mi) · Hamlin County (29 mi) · Spink County (30 mi) · Day County (35 mi) · Kingsbury County (36 mi) · Beadle County (41 mi).