Barnwell is a city located in Barnwell County, South Carolina, United States. It is the county seat of Barnwell County and has a population of approximately 4,126 residents as of the 2020 census. The city is known for its historic downtown area, which features a variety of shops, restaurants, and landmarks. Barnwell is also home to various industries, including manufacturing and agriculture. It offers a small-town atmosphere with close-knit community values.