When you are sending anything to a physical address, whether that be packages, cards, or documents, it will be beneficial to know the abbreviation of the state you are sending things to. The South Carolina abbreviation is slightly trickier than most two-letter US postal abbreviations, this is because the state name is made up of two words. The South Carolina two-letter abbreviation is the first letter of each word in the state’s name: “SC”.

Source: Foreign USA