Fortree City is a city, roughly between Mauville and Lilycove, in the Hoenn region. In the West are Route 119 and the Weather Institute. In the East Route 120 and the Safari Zone. The city's motto is "The Treetop City that Frolics with Nature."

The residents of Fortree City live in treehouses and get around by a system of rope bridges that hang in the treetops. Because of the physical exertion needed for such a lifestyle, they are all healthy and fit, and by preserving Foretree's natural environment they are able to live nearer to wild Pokémon than the residents of most other cities. Wild Bug-type Pokémon often fly in through the windows, and from time to time wild Kecleon will block paths in the city. The heavy rainfall saturates the soil and lets the trees to grow tall. This is why Fortree City's trees are so much taller than trees elsewhere.