History of Barnwell County, South Carolina in Timeline

By Popular Timelines Editorial Team · Updated: April 23, 2026

Barnwell County is located in South Carolina, within the Central Savannah River Area. The county's seat is Barnwell. The population was 20,589 as of the 2020 census.

1919: Formation of Allendale County

In 1919, the southern half of Barnwell County was used to form most of the new Allendale County, reducing Barnwell County to its current size.

1948: Democratic Party stronghold

Prior to 1948, Barnwell County was a Democratic Party stronghold.

1952: Democratic wins

In 1952, Democratic won in Barnwell County.

1956: Democratic wins

In 1956, Democratic won in Barnwell County.

1960: Republican wins

In 1960, Republican won in Barnwell County.

1964: Republican wins

In 1964, Republican won in Barnwell County.

1968: Transitional time for politics

By 1968, Barnwell County's politics were in a highly transitional time.

1972: Primarily Republican

From 1972 on, Barnwell County has primarily Republican.

2000: Swing county

From 2000, the county has become more of a swing county.

2000: Barnwell County Demographics

In 2000, Barnwell County had a population of 23,478 people residing in 9,021 households and 6,431 families. The population density was 43 people per square mile. The racial makeup of the county was 55.18% White and 42.55% Black or African American.

2010: Population and Demographics of Barnwell County

In 2010, Barnwell County had a population of 22,621 people, 8,937 households, and 6,055 families. The population density was 41.2 inhabitants per square mile. The racial makeup was 52.6% white, 44.3% Black or African American, 0.6% Asian, 0.4% American Indian, and 1.5% from two or more races.

2010: School District Not Defined

In 2010, a portion of Barnwell County was labeled as 'School District Not Defined' by the U.S. Census, corresponding to the Savannah River Site.

2017: Barnwell County's Real GDP

In chained 2017 dollars, Barnwell County's real GDP was $448.3 million (approx. $21,774 per capita).

2020: Demographics of Barnwell County

In 2020, Barnwell County had a population of 20,589 people, with 8,460 households and 5,260 families. The median age was 42.5 years, with 22.5% under 18 and 19.2% over 65. The county had 92.2 males per 100 females.