European colonization and later history

The first European colonists to arrive in the area were Welsh settlers, part of the British Isles colonists who migrated south from Pennsylvania. In 1737, they established the first European-American settlement, called Welsh Neck.^[8] These settlers organized a Baptist church in January 1738.^[9]

The South Carolina Welsh settlement consisted of 173,000 acres granted exclusively to Welsh settlers in 1737 by an act of the South Carolina Assembly. Within a decade, nearly all of this land had been taken and settled in by Welsh immigrants, the majority of whom were Baptists. They immigrated to what is now Marlboro County, South Carolina from existing Welsh settlements in Delaware and Pennsylvania as well as directly from Wales. The European settlement along the Peedee River from area around Poston and Gresham, South Carolina all the way to the area around McFarlan, North Carolina was exclusively Welsh between the 1730s and the 1780s.^[10]

On 12 March 1785, Marlboro County was established by the South Carolina General Assembly according to its powers as described in the 1778 Constitution of the State of South Carolina during the American Revolution. It was named for the Duke of Marlborough.^[11] The nascent county remained part of what was then known as Cheraws District until 1798, then in 1800 Marlboro became a district itself. Under the 1868 Constitution of the State of South Carolina, passed during the Reconstruction era, South Carolina districts became counties with home rule, where the legislative representatives from each county had additional powers as councillors of their county.

The first courthouse was built near the Great Pee Dee River, just north of Crooked Creek, in a village called Carlisle, named for Richard Carlisle.

To establish a central location for the county court, the state legislature designated Bennettsville, founded in 1819, as the new county seat. Construction for a courthouse, designed by Robert Mills, began in 1820. and was completed in 1824.^[8] It was replaced in the later 19th century. The second courthouse was expanded and renovated in 1953–1954.

State and local protected area

• Lake Paul Wallace Wildlife Management Area^[13]

Major water bodies

• Crooked Creek
• Little Pee Dee River
• Great Pee Dee River
• Lake Wallace

Adjacent counties

2020 census

As of the 2020 census, there were 26,667 people, 9,613 households, and 6,069 families residing in the county.

2010 census

At the 2010 census, there were 28,933 people, 10,383 households, and 6,903 families in the county.^[19][4] The population density was 60.3 inhabitants per square mile (23.3 inhabitants/km²). There were 12,072 housing units at an average density of 25.2 units per square mile (9.7 units/km²).^[20] The racial makeup of the county was 50.9% black or African American, 41.4% white, 4.5% American Indian, 0.3% Asian, 1.1% from other races, and 1.8% from two or more races. Those of Hispanic or Latino origin made up 2.8% of the population.^[19] In terms of ancestry, and 9.7% were American.^[21]

Of the 10,383 households, 33.5% had children under the age of 18 living with them, 36.8% were married couples living together, 24.3% had a female householder with no husband present, 33.5% were non-families, and 30.0% of households were made up of individuals. The average household size was 2.47 and the average family size was 3.06. The median age was 38.8 years.^[19]

The median household income was $27,688 and the median family income was $32,485. Males had a median income of $31,170 versus $24,885 for females. The per capita income for the county was $13,817. About 23.3% of families and 27.5% of the population were below the poverty line, including 40.4% of those under age 18 and 17.6% of those age 65 or over.^[22]

2000 census

At the 2000 census, there were 28,818 people, 10,478 households, and 7,334 families in the county. The population density was 60 people per square mile (23 people/km²). There were 11,894 housing units at an average density of 25 units per square mile (9.7 units/km²). The racial makeup of the county was 50.73% Black or African American, 44.49% White, 3.36% Native American, 0.24% Asian, 0.24% from other races, and 0.95% from two or more races. 0.71% of the population were Hispanic or Latino of any race.^[23] Of the 10,478 households 32.00% had children under the age of 18 living with them, 42.60% were married couples living together, 22.20% had a female householder with no husband present, and 30.00% were non-families. 26.90% of households were one person and 11.00% were one person aged 65 or older. The average household size was 2.59 and the average family size was 3.14.

The age distribution was 26.20% under the age of 18, 9.30% from 18 to 24, 29.40% from 25 to 44, 22.80% from 45 to 64, and 12.30% 65 or older. The median age was 35 years. For every 100 females there were 96.30 males. For every 100 females age 18 and over, there were 93.10 males.

The median household income was $26,598 and the median family income was $32,019. Males had a median income of $25,896 versus $20,590 for females. The per capita income for the county was $13,385. About 17.70% of families and 21.70% of the population were below the poverty line, including 29.20% of those under age 18 and 22.70% of those age 65 or over.

Major highways

• Future I-73
• I-95
• US 1
• US 15
• SC 9
• 
  SC 9 Bus.
• SC 34
• SC 38
• 
  SC 38 Bus.
• SC 79
• SC 83
• SC 177
• SC 381
• SC 385
• 
  SC 385 Conn.
• SC 912

Airports

• Marlboro County Jetport
• Myrtle Beach International Airport (MYR), 76.8 miles southeast of Bennettsville
• Charlotte International Airport (CLT), 81.3 miles northwest of Bennettsville
• Clio Crop Care Airport (9W9)

Cities

• Bennettsville (county seat and largest community)
• Cheraw (mostly in Chesterfield County)

Towns

• Blenheim
• Clio
• McColl
• Tatum

Census-designated places

• Wallace