Mt. Chimney is a volcanic mountain located in the northern half of Hoenn, directly northeast of Lavaridge Town. At its southern base lies Route 112, the Cable Car Base Station, and both the northern and southern openings of Fiery Path, a tunnel through the mountain itself. The Cable Car line inclines up the side of the volcano northwesterly until it reaches the other terminal at the peak. Here a choice can be made to continue on the short ascent to the magma crater of Mt. Chimney, or take Jagged Pass descending the south side of the mountain; a trek littered with ledges, mountainous foliage and ash-covered grass hiding wild Pokémon, then finally vacating back onto Route 112, on a pathway west to Lavaridge.
The volcano accumulates a vast cloud of soot above it which rains ash down upon Route 113 to the north, leaving the grass and trees in the area layered in residue.
Mt. Chimney appeared in Fight For the Meteorite, where Ash and his friends took the cable car up there, with a disguised Team Rocket joining them. However, the cable car's power was shut down midway through, forcing Ash to climb to Mt. Chimney across the cable to get help. At the mountain, Professor Cozmo was searching for the Meteorite, but as soon as he had managed to find it, Team Magma and Team Aqua appeared, both intending to steal the Meteorite for themselves.
Although Ash and Cozmo managed to evade the villainous teams for a while, the Meteorite was eventually stolen by Team Magma, who placed it inside a laser machine with the intent of making Mt. Chimney erupt. As there was no time to get the Meteorite out of the machine, Cozmo chose to push it into the volcanic crater, destroying the Meteorite in the process and foiling Team Magma's plan. After Ash's friends and Team Rocket were rescued from the cable car, Cozmo guided the group to take the Jagged Pass to reach Lavaridge Town before parting ways with them.
According to promotional posters, Mt. Chimney is located northeast of Forina.
In Pokémon Adventures it is stated that Mt. Chimney is an integral part of the water cycle of the Hoenn region, as the heat emitted by it evaporates water from the sea around the region. In the Ruby & Sapphire chapter, Team Aqua succeeded in ending the volcanic activity of Mt. Chimney by tricking Professor Cozmo to use the meteorite he had found to power up their machinery. Sapphire, despite defeating Aqua Admin Matt, failed to stop their mission. Tabitha and Flannery attempted to revive the volcano but were unsuccessful. The cessation of volcanic activity resulted in the region cooling off, which in turn caused the sea level to rise and flooding in the region. The disruption of the natural balance was also one reason for Kyogre and Groudon's awakening.
The event was one of very few that Gabby and Ty could not report on, because of the order from their boss (which turns out to be Team Aqua's leader, Archie).
After Kyogre and Groudon stopped fighting, it was reported that Groudon chose Mt. Chimney as its new resting place.
In Generation III Hoenn games, all waves and flowers blow in the wind to the southwest. Despite this, ash from Mt. Chimney is constantly falling to its north, on Route 113.
A man in Verdanturf Town, which is located to the southwest of Mt. Chimney, says that the wind never blows volcanic ash in that direction. However, the wind should inevitably carry ash there.