Stumpy Ridge is a landmark in Fortnite, so won’t show up on any maps in the game. Finding it is quite simple though, as it is is in a well-traveled part of the island. You can find Stumpy Ridge to the east of Weeping Woods and Slurpy Swamp.
The area is made up of some small embankments with lots of tree stumps on it, and quite a few trees still standing in the area as well. This makes it a great spot to farm for a lot of wood if you are in need of it.
Stumpy Ridge is not really the best spot for loot, but if you are starting a game here you can find two chests, and usually two pieces of ground loot as well, so you will at least be able to get somewhat of a loadout together. After that, your will want to make your way into Weeping Woods, down to Slurpy Swamp, or across to Layz Lake/Hydro 16 to get some proper looting options going.
The main reason to visit Stumpy Ridge is primarily for any challenge that is in the area, such as the Chapter 2 Season 7 challenge to plant saplings in the area.