Charlotte Harbor (southwest Florida bay), the second largest bay in Florida is located on the Gulf of Mexico coast of west Florida, mostly (2/3) in Charlotte County, Florida with the remaining 1/3 in Lee County. The area is also identified as the Charlotte Harbor Estuary. The harbor's mouth is located behind Gasparilla Island, one of the many coastal barrier islands on the southwest coast of Florida, with access from the Gulf of Mexico through the Boca Grande Pass between Gasparilla Island on the north and Lacosta Island on the south. Charlotte Harbor covers about 270 sq mi (700 km2)