Merritt Island is a peninsula, commonly referred to as an island, in Brevard County, Florida, United States, located on the eastern Florida coast, along the Atlantic Ocean. It is also the name of an unincorporated town in the central and southern parts of the island and a census-designated place. The population was 34,518 at the 2020 census, down from 34,743 at the 2010 census. It is part of the Palm Bay–Melbourne–Titusville, Florida Metropolitan Statistical Area. NASA's John F.