Horry County was formed in 1802 from the old Georgetown District. The first land grants in this area were in 1735. Bear Bluff and Black Lake were sites of some Revolutionary War skirmishes. Francis "Swamp Fox" Marion is supposed to have camped in Kingston (present day Conway) en route to the Battle of Black Mingo. Horry was named for Brigadier General Peter Horry, Kingston was renamed to Conwayborough for Brigadier General Robert Conway. In 1898, Conwayborough shortened it's name to Conway as it incorporated. (Some 166 years after it's founding in 1732.) Horry County is probably best known today as a tourist destination, the Myrtle Beach area is very popular with tourists. Surfside Beach as a family vacation destination has been promoted by the town of Surfside Beach (to the south of Myrtle Beach).
A more detailed History of Horry County, South Carolina can be found here.