The Giant Ghana Snail. With a shell that commonly grows to a length of 18cm and a diameter of 9cm, but has been observed to grow as large as 30x15cm, the giant Ghana snail is the world's largest land snail. Native to West Africa, giant Ghana snails can be found within 160 to 305 klm of the coasts of Sierra Leone, Liberia, Ivory Coast, Togo, Benin, Nigeria, & Ghana.