Gengoro Island is an island on Earth, located east of Kame House and General Blue's Camp. It is where Penguin Village is located on. It is also Dragon World's version of the real world country Japan.
Gengoro Island is mostly composed by grassy plains, but some hills and small lakes can also be found here.
In the Dr. Slump special chapter "Kick the Can", Senbei Norimaki is seen running all over a map of Gengoro Island searching through the other towns of Gengoro Island for Arale and Gatchan. The various locations noted on the map other than Penguin Village are: Dumbtown, Needwife, Overthere, Mountain, Land I, Bigshore, Nowheresville, Bigtown, Poop, Station, Boonyville, Fartown, Harbor, and ABC.
Big City Island
Wonder Island (ワンダーアイランド) is a strange island shaped like a question mark that is located a distance from Gengoro Island. It is the primary setting to Akira Toriyama's first published manga, Wonder Island. In Dr. Slump, Senbei Norimaki, Arale Norimaki, and Gatchan travel to this island in order to obtain a tear from the Ogre-king Gyaska to make the Fall-Go-Boom Love Potion for Senbei.
Many creatures mostly based off Japanese fairy tails live there. Wonder Island is notably the home to P-Man, a fairy, flying fish, monkeys, a hang-gliding gorilla, a witch, vampires, dinosaurs, an angel, frogs, and a dragon. King Ghidorah, Little Red Riding Hood, Momotaro, and Kintarō are also seen there.
There are buses that offer trip to Wonder Island in Penguin Village.