Beaufort County is a county in the U.S. state of South Carolina. As of the 2020 census, its population was 187,117. Its county seat is Beaufort and its largest community is Hilton Head Island. Beaufort County is part of the Hilton Head Island-Bluffton-Port Royal, SC Metropolitan Statistical Area. It is one of the South's fastest-growing counties, primarily because of development south of the Broad River clustered along the U.S. Highway 278 corridor.