Global Range: (20,000-200,000 square km (about 8000-80,000 square miles)) Range encompasses rivers, estuaries, and coastal areas of subtropical and tropical areas of northern South America, West Indies/Caribbean region (but apparently never very abundant in the Greater Antilles, except perhaps Cuba, Lefebvre 1989), Gulf of Mexico (now mainly western and southwestern portions), and southeastern North America (mainly Florida).
Present range limits are similar to those known historically, but the distribution is fragmented due to areas of local extirpation (O'Shea and Ludlow 1992). Area of occupancy and abundance are apparently greatly reduced in Central and South America compared to the historical situation. Small numbers exist in the Greater Antilles but the species has not been documented in the Lesser Antilles south of the Virgin Islands since the 1700s. Sightings are rare in the Bahamas. Manatees remain relatively abundant in Belize (compared to elsewhere in Central America) and in Guyana, and they are still reasonably abundant in some areas of Mexico and on both coasts of Florida (Lefebvre et al. 1989). In Puerto Rico, manatees are most often observed in coastal areas from San Juan eastward to the east coast, (and including Vieques Island) and then south and west, past Jobos Bay, to the west coast, and about as far to the northwest as Rincon; they are concentrated in several areas, including Ceiba, Vieques Island, Jobos Bay, and Boquerón Bay, and are less abundant along the north coast, between Rincón and Dorado (USFWS 2007). Manatees are very rare (transient) in the U.S. Virgin Islands (USFWS 2007). See Fairbairn and Haynes (1982) and Hurst (1986) for information on status and distribution in Jamaica. See Lefebvre et al. (1989) for a fairly detailed overview of country by country status.
U.S. populations occur primarily in Florida (e.g., see Van Meter 1987), where they are effectively isolated from other populations by the cooler waters of the northern Gulf of Mexico and the deeper waters of the Straits of Florida (Domning and Hayek 1986). In the southeastern United States, manatees are more or less retricted to the vicinity of warm-water sites in peninsular Florida during the winter, although a few may remain year-round in Cumberland Sound, southeastern Georgia, where factory warm-water outfalls allow survival of colder winter months (Reeves et al. 1992). Occasional manatees occur in summer from Texas to North Carolina (e.g., see Schwartz 1995, Brimleyana 22:53-60, for North Carolina records). Those in Texas may be wanderers from Mexican population, but DNA analysis of an individual captured linked it to the Florida population (T. Ettel, pers. comm.). Manatees range along most of the Gulf coast of Florida but infrequently occur north of the Suwannee River and between the Chassahowitzka River and Tampa Bay. They inhabit the Atlantic coast of Florida from the Georgia coast to Biscayne Bay and the Florida Keys, including the St. Johns River, the Indian River lagoon system, and various other waterways (O'Shea and Ludlow 1992). In Florida, the most well-used wintering areas are at Crystal River, Homosassa River, Tampa Bay, Ft. Myers, Port Everglades, Riviera Beach, near Titusville, and Blue Spring (O'Shea and Ludlow 1992).