Bryan County was the 16th county formed in Georgia from parts of Chatham county.  It was named for Jonathan Bryan, an American Revolutionary War partisan, a member of the King's Council who accompanied Oglethorpe and an early critic of oppressive English Rule.

The first county seat was in Hardwick, however in 1860 the seat was moved to Eden, Georgia.  By 1901 the county seat was located in Clyde, which may have been the same location formerly known as Eden.  In 1937 Pembroke took over the role as county seat due to the establishment of Camp Stewart (now Fort Stewart) on the site of Clyde.  The only remaining sign of Clyde is a cemetary on the military reservation.