9,330 people (2024 Census estimate, +11.8% since 2020)
1,557 square miles of land · 6 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.
11 active community water systems list Custer County in the area they serve, reporting 4,006 people served in all (a system that crosses county lines counts its whole population).
| CUSTER groundwater · local government · SD4600101 | 1,919 served |
| SOUTHERN BLACK HILLS WATER groundwater · private · SD4602309 | 947 served |
| HERMOSA-OLD SYSTEM groundwater · local government · SD4600154 | 420 served |
| SPRING CREEK ACRES groundwater · private · SD4602252 | 172 served |
| BUFFALO GAP groundwater · local government · SD4600077 | 126 served |
| HERMOSA WATER USERS ASSOCIATION groundwater · local government · SD4602180 | 108 served |
| HEARTLAND COUNTRY RANCHETTES groundwater · private · SD4602235 | 95 served |
| ROCK RIDGE COURT groundwater · private · SD4602209 | 74 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 Custer County's jail, in Vera's latest figure (1970), or 105 per 100,000 residents ages 15–64.
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 Custer County. School taxes are usually the largest part of a property tax bill.
Spent $14.5 million — $13.4 million to run schools, about $14,663 per student, plus $574,000 on buildings and equipment. Money in: $13.8 million local (mostly property tax), $305,000 state, $2.6 million federal. Long-term debt: $20.2 million.
Spent $435,000 — $368,000 to run schools, about $33,455 per student, plus $67,000 on buildings and equipment. Money in: $288,000 local (mostly property tax), $3,000 state, $83,000 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: Very Low compared with other U.S. counties. FEMA estimates natural hazards cost Custer County about $8.8 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Moderate; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
94 bridges in Custer County: 47 in good condition, 42 fair, and 5 poor (5.3%). “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.
| STATE PARK RD over CENTER LAKE INLET · built 1950 | 1,000 vehicles a day |
| E MAIN ST FAS 6488 over BEAVER CK · built 1971 | 108 vehicles a day |
| STATE PARK RD over GRACE COOLIDGE CREEK · built 1950 | 100 vehicles a day |
| STATE PARK RD over GRACE COOLIDGE CREEK · built 1950 | 100 vehicles a day |
| STATE PARK RD over CK · built 1950 | 5 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $4.6 million of work in Custer County in fiscal 2025, about $548 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 Custer 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 Custer County built: brayden.ozark@gmail.com.
More of South Dakota: the state government and every county in South Dakota.
Nearby counties: Fall River County (32 mi) · Pennington County (39 mi) · Lawrence County (49 mi) · Oglala Lakota County (51 mi) · Weston County, WY (56 mi) · Niobrara County, WY (66 mi).