Garter snakes hail from much of North America though as I'm sure you can guess the warmer areas tend to have a greater profusion.
Some species of garter snakes may also be found in Mexico (such as Thamnophis eques) but except for escaped pets
are not found on other continents.
Within these confines, garter snakes live generally near standing water such as ponds, irrigation ditches and other moist
areas though in captivity their substrate should not be allowed to get damp or skin problems can occur.