Sebastian is a city in Indian River County, Florida, United States. In 2010, the population recorded by the U.S. Census Bureau was 21,929.
Sebastian is a principal city of the Sebastian−Vero Beach Metropolitan Statistical Area, which includes all of Indian River County.
The town of Sebastian was a fishing village as early as the 1870s. In the early 1880s David Peter Gibson, and Thomas New settled in the area. New filed to start a post office under the name New Haven. However, New got into legal trouble for misuse of his position as postmaster and was removed. Sebastian was officially founded in 1882 and named St. Sebastian, after Saint Sebastian.