Rex is an unincorporated community in Clayton County, Georgia, United States. Its elevation is 797 feet. Although Rex is unincorporated, it has a post office, with the ZIP code of 30273; the ZCTA for ZIP Code 30273 had a population of 11,412 at the 2000 census.The Historic Rex Village was identified as a place in peril by the 2011 Georgia Historic Trust.