Beaufort County has historically been one of the most poorly botanized counties in the state. Geographically, it lies farther from the major research institutions than most other counties and has therefore received little attention from modern botanists. Major waterways, numerous private communities and an oppressive summer climate further complicate botanical research. Beaufort has one of the fastest growing human populations in the state. Natural areas are rapidly being converted into residential and commercial developments. An understanding of the county's flora is necessary to focus conservation efforts to preserve critical habitat and develop management plans for maintaining biodiversity. This project was conducted to help provide that data. Between 2003 and 2010, over 3000 voucher collections were made from various plant communities throughout the county. Previous collections housed at the Clemson and Citadel herbaria were also examined. Special emphasis was placed on documenting populations of rare plants, invasive plants and new state occurrences. In total 1597 native and naturalized taxa were documented. Prior to this study, 938 taxa were reported for the county. This study has added an additional 659. More than 200 of these were not previously reported for South Carolina in the most recent atlas. Some represent range extensions of native species which should be considered for inclusion to South Carolina Rare List. Information is provided about the new state records and the more significant county records. Many of the new records consist of species which are exotic and may warrant special attention due to the threat they may pose to natural ecosystems and agriculture.