Fairfield County area

Population and density of Fairfield County

The Census Bureau estimates that 20,340 people lived in Fairfield County on July 1, 2025. That ranks #1,865 of 3,222 county equivalents nationally and #39 of 46 in South Carolina. Since the April 1, 2020 estimates base of 20,961, the population has declined by 621 (−3%), compared with +8.8% for South Carolina as a whole.

With 686.3 square miles of land, that is 30 people per square mile (11 per km²), placing Fairfield County #2,017 nationally for density and #44 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 22 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 Fairfield County

4 incorporated places lie at least partly in Fairfield County. Together they are home to 3,745 people (18.4%); the other 16,595 (81.6%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Winnsboro town, with 3,305 residents in the county. By land, Blythewood town is the largest at 10.6 mi² across all its counties.

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

Metropolitan area

Fairfield County is an outlying county of the Columbia, SC Metropolitan Statistical Area. Its 6 county equivalents have 879,918 residents on 3,703.2 square miles of land; Fairfield County accounts for 18.5% of the land and 2.3% of the residents. By combined land it ranks #79 of 393 metropolitan areas, and #72 by population. It belongs to the Columbia-Sumter-Orangeburg, SC Combined Statistical Area.

ZIP codes

9 ZIP Code Tabulation Areas have land in Fairfield County; 5 of them have most of their land inside the county, and the others mainly cover neighboring areas.

290142901529016290312904529055290652913029180

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 Fairfield County

Fairfield County shares a land border with 6 county equivalents. It has more land than 4 of them. The largest neighbor is Richland County (757.3 mi²) and the smallest is Union County (513.6 mi²). Together with its neighbors, Fairfield County forms a block of 4,444.2 mi² of land, of which it holds 15.4%.

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

Fairfield County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.5 times as much. South Carolina’s county land could hold about 44 areas the size of Fairfield County.

Another way to picture it: the same land area would fill a square about 26.2 miles (42.2 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 Fairfield County?

Fairfield County has more land than 1,855 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 Fairfield County at #1,417 nationally by total area, 50 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 3.3%, compared with a national county-equivalent median of 1.2% — 2.2 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 Fairfield 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.