It is the location of the Topper Site, an archeological excavation providing possible evidence of a pre-Clovis culture dating back 50,000 years.

The site is near a source of chert on private land in Martin owned by Clariant Corporation, a Swiss chemical company with a plant there.

The site, named after John Topper, a nt who discovered it, has been under excavation by archeologists from the University of South Carolina for about one month a year since 1999, after an initial exploratory dig in the mid-1980s.

The original Allendale County Courthouse burned down in May 1998, with reconstruction begun in August 2002.

[4][5] During the Civil Rights movement, the Courthouse almost became a site for a sit-in protest after African-American citizens charged officials with deliberately delaying the voter registration of Black residents.

[9] The Savannah River forms the county's western border with Georgia.

Before interstate highways were built, Allendale had several motels, primarily serving travelers in-between Northeastern states and Florida.

[25] Allendale County has a five-member council elected from single-member districts.

Senate District 40 has been represented by Democrat and Minority Leader Brad Hutto since 1996.

[31] Democrat Margie Bright Matthews has represented District 45 since 2015, after she was elected to the position to fulfill the unexpired term of Clementa C.

[66] In the 2008 U.S. presidential election Barack Obama received 75.3 percent of the county's vote.

[67] In the 2012 U.S. presidential election Barack Obama received 79.2 percent of the county's vote.

[72] As of April 2024[update], some of the largest employers in the county include Atlantic Power Corporation, AZ Electronic Materials, Georgia-Pacific, South Carolina Department of Corrections (SCDC), and the University of South Carolina.

[73] The county is also the site of WEBA, Channel 14, a broadcast outlet of the South Carolina Educational Television Network.

The former C. V. Bing High School served African-American students until desegregation.

The last local news publications, The Citizen-Leader and The Allendale Sun, stopped printing in 2014 and 2015, respectively.