An extensive review of published record data, and the amassing of new collection data from the study of numerous collections and surveys has led to the accounting of 182 species of Ephemeroptera from the state of South Carolina. Previous listings are corrected, and all species are supported by previously available or, for the most part, new collection data. Twenty-two species are listed for the state for the first time, and supporting data are provided for the first time for another 39 species. Three species previously listed for South Carolina are discounted. Over 1000 new county records are given for 160 of the species and all 46 state counties.