The Great Blue Heron is found throughout most of North America, as far north as Alaska and the southern Canadian provinces in the summer. In winter, the range extends south through Florida, Mexico, and the Caribbean to South America. Birds east of the Rocky Mountains in the northern part of their range are migratory and winter in the coastal areas of the Southern United States, Central America, or northern South America. From the Southern United States southwards, and on the lower Pacific coast, they are year-round residents. However, their hardiness is such that individuals often remain through cold northern winters, as well, so long as fish-bearing waters remain unfrozen (which may be the case only in flowing water such as streams, creeks, and rivers).
The Limpkin undertakes some localized migrations, although the extent of these is not fully understood. In some parts in the northern part of the range, females (and a few males) leave the breeding areas at the end of summer, returning at the end of winter In Brazil, birds breeding in some seasonal marshes leave during the dry season and return again with the rains. Birds may also migrate between Florida and Cuba, as several limpkins on the Florida Keys and Dry Tortugas have been reported, but these records may also represent vagrants or post-breeding dispersal. One study in Florida using wing tags found limpkins dispersed up to 325 km (202 mi) away from the breeding site. This tendency may explain vagrant limpkins seen in other parts of the United States and at sea near the Bahamas.