Fortree City is a city located roughly between Mauville City and Lilycove City in the Hoenn Region. The city is nicknamed, "The treetop city that frolics with nature."
The residents of Fortree City live in treehouses and traverse the city by crossing rope bridges that connect the treehouses. Unlike most other cities, Fortree City is located in the midst of Pokémon wilderness. Bug-type Pokémon fly through the windows, and invisible Kecleon often block pathways. Heavy rainfall makes the trees in Fortree City grow. This is why the trees are so much taller than trees located elsewhere.
Fortree City is also home to gym leader Winona, specializing in flying-type Pokémon. After defeating her, the challenger is awarded the Feather Badge, which allows the player to use the HM Fly outside of battle, as well as TM40, Aerial Ace. At first, the Fortree Gym is unaccessible due to a Kecleon blocking the way. So the player must use the Devon Scope, given to on Route 120 by Steven. With it, the player gains access to the Fortree Gym, which is formed by rotating doors that turn when the player walks through them.
In the anime, Ash and his friends stay in Fortree City throughout the episodes Who's Flying Now? and Sky High Gym Battle! Fortree City throws a festival called the Feather Carnival to celebrate wild flying-type Pokémon.