Seffner is a census-designated place in Hillsborough County, Florida, United States. The population at the 2020 census was 8,362, up from 7,579 at the 2010 census. Located approximately 13 miles east of downtown Tampa, Seffner is considered a suburb. Though still characterized by towering live oak trees, strawberry farms and lakes, Seffner has been growing rapidly in recent years, with housing subdivisions being added to the once rural landscape.