25,498 people (2024 Census estimate, −3.8% since 2020)
480 square miles of land · 53 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.
5 active community water systems list Marlboro County in the area they serve, reporting 21,313 people served in all (a system that crosses county lines counts its whole population).
| BENNETTSVILLE CITY OF (SC3410001) surface water · local government · SC3410001 | 9,168 served |
| MARLBORO WATER CO (SC3420001) groundwater · private · SC3420001 | 5,360 served |
| WALLACE WATER COMPANY buys surface water · local government · SC3420002 | 3,552 served |
| MCCOLL TOWN OF (SC3410003) groundwater · local government · SC3410003 | 2,445 served |
| CLIO TOWN OF (SC3410002) groundwater · local government · SC3410002 | 788 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 48 people were held in Marlboro County's jail, in Vera's latest figure (2019), or 271 per 100,000 residents ages 15–64. In 2014 it was about 61.
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.
1 school district has its office in Marlboro County. School taxes are usually the largest part of a property tax bill.
Spent $65.3 million — $54.7 million to run schools, about $15,403 per student, plus $8.1 million on buildings and equipment. Money in: $17.3 million local (mostly property tax), $31.2 million state, $18.4 million federal. Long-term debt: $62.4 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: Relatively Low compared with other U.S. counties. FEMA estimates natural hazards cost Marlboro County about $11.4 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very Low; social vulnerability: Very High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
97 bridges in Marlboro County: 35 in good condition, 55 fair, and 7 poor (7.2%). “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.
| SC 9 BUS over CROOKED CREEK · built 1921 | 10,100 vehicles a day |
| SC 9 over PHILLIS CREEK · built 1932 | 8,300 vehicles a day |
| US 15 over PANTHER CREEK · built 1925 | 7,600 vehicles a day |
| US 1 NB over GREAT PEE DEE RIVER · built 1962 | 7,400 vehicles a day |
| SC 9 SB over NAKED CREEK · built 1975 | 4,150 vehicles a day |
| SC 83 over LITTLE PEE DEE RIVER · built 1937 | 550 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $1.5 million of work in Marlboro County in fiscal 2025, about $56 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 Carolina 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 Marlboro 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 Marlboro County built: brayden.ozark@gmail.com.
More of South Carolina: the state government and every county in South Carolina.
Nearby counties: Scotland County, NC (20 mi) · Dillon County (23 mi) · Darlington County (25 mi) · Chesterfield County (27 mi) · Richmond County, NC (28 mi) · Robeson County, NC (33 mi).