ThunderClan claims the northeastern part; their territory is mainly deciduous woodland. Their camp is an abandoned Twoleg quarry, called the stone hollow by the cats.

Landmarks in the ThunderClan territory:
-The Sky Oak, a large tree near the shore.
-A mossy clearing where apprentices train.
-North of the camp is an abandoned Twoleg Nest, a location rich in prey and herbs.
-A network of tunnels running below ThunderClan and WindClan grounds, connecting them.
-A clearing near the ShadowClan border where Twolegs camp in greenleaf.
-An abandoned, unpaved road (named The Old Thunderpath by the cats) starting from the hollow and heading north.

The ThunderClan Lake Camp is in an abandoned quarry, described as a stone hollow enclosed by tall cliffs. The main entrance is through a thorn tunnel, which can lead out of the camp after exiting the dirtplace. There is also a secret entrance that is reached by climbing the rocks. The walls offer protection and keep out the wind, but cats must watch their step near the edge as falling into the hollow can be fatal. A tall rock called the Highledge is used by the leader to call meetings. Most of the dens consist of caves and crevices in the rock wall. There is also a Halfrock, which is a smooth low stone that rises out of the ground near the elders den. At one point, badgers devastated the camp, but it was rebuilt by the cats.

•The nursery is under a thick bramble bush reinforced with thick roots woven together for protection. It's floor is made of packed earth.
•The apprentices', leader's, and medicine cat's dens are caves in the rock, entrances hidden by bramble tendrils.
•The warriors' den is in a dip in the ground under a big thorn bush, and after the tree falls in Fading Echoes, it is rebuilt under the branches of a beech tree.
•The elders' den is in a hazel bush, and later is rebuilt under the boughs of a beech tree and reinforced with honeysuckle.