Sumter County area

Population and density of Sumter County

The Census Bureau estimates that 105,067 people lived in Sumter County on July 1, 2025. That ranks #603 of 3,222 county equivalents nationally and #16 of 46 in South Carolina. Since the April 1, 2020 estimates base of 105,557, the population has declined by 490 (−0.5%), compared with +8.8% for South Carolina as a whole.

With 665.1 square miles of land, that is 158 people per square mile (61 per km²), placing Sumter County #750 nationally for density and #16 in South Carolina. The median county equivalent has 47 people per square mile; the South Carolina median is 78. Put another way, there are about 4.1 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Sumter County

3 incorporated places lie at least partly in Sumter County. Together they are home to 44,146 people (42%); the other 60,921 (58%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Sumter city, with 43,094 residents in the county.

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Sumter County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Sumter County is a central county of the Sumter, SC Metropolitan Statistical Area. Sumter County is the area’s only county equivalent, so the metro area has the same 665.1 square miles of land. By combined land it ranks #330 of 393 metropolitan areas, and #357 by population. It belongs to the Columbia-Sumter-Orangeburg, SC Combined Statistical Area.

ZIP codes

15 ZIP Code Tabulation Areas have land in Sumter County; 9 of them have most of their land inside the county, and the others mainly cover neighboring areas.

290012904029051290622908029104291142912529128291502915229153291542916229168

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Sumter County

Sumter County shares a land border with 6 county equivalents. It has more land than 3 of them. The largest neighbor is Florence County (800.5 mi²) and the smallest is Calhoun County (381.1 mi²). Together with its neighbors, Sumter County forms a block of 4,348 mi² of land, of which it holds 15.3%.

How big is Sumter County compared with U.S. states?

Sumter County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.6 times as much. South Carolina’s county land could hold about 45 areas the size of Sumter County.

Another way to picture it: the same land area would fill a square about 25.8 miles (41.5 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Sumter County?

Sumter County has more land than 1,809 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Sumter County at #1,486 nationally by total area, 73 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 2.5%, compared with a national county-equivalent median of 1.2% — 1.3 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Sumter County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.