St. Simons Island is a barrier island and census-designated place located on St. Simons Island in Glynn County, Georgia, United States. The names of the community and the island are interchangeable, known simply as "St. Simons Island" or "SSI", or locally as "The Island". St. Simons is part of the Brunswick metropolitan statistical area, and according to the 2020 U.S. census, the CDP had a population of 14,982.