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.
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 triggering Mt. Chimney's eruption. 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 and foiling Team Magma's plan. After Ash's friends and Team Rocket were rescued from the cable car, Cozmo instructed the group to take the Jagged Pass to reach Lavaridge Town before parting ways with them.
In Absol Absolved!, Ash and Goh visited Mt. Chimney to figure out the cause behind Lavaridge Town's hot springs drying out. The townspeople blamed an Absol for the incident, but as Ash and Goh climbed up the volcano, they discovered a group of Glalie having moved on the mountain and frozen over a part of it to make it a more suitable habitat for themselves. Ash and Goh realized that the Glalie had frozen the source of the hot springs, but were stopped from approaching them by Absol. As Goh looked deeper into Lavaridge Town's history, he discovered that a similar incident had happened before, and all the ice melting at once had caused a phreatic eruption. Working together with Absol, Ash, and Goh were able to prevent the eruption and restore water to the hot springs. In the process, Absol ended up joining Goh's team after he caught to save it from being hit by boiling-hot water. The people of Lavaridge Town also agreed to take the Glalie to a place better suited for them.
According to promotional posters, Mt. Chimney is located northeast of Forina.
In Short Shrift for Shiftry, the cooling of Mt. Chimney was revealed to have resulted in the region itself cooling down as well and the sea levels rising. This, in turn, had resulted in the energy balance of Hoenn being disrupted and Groudon and Kyogre moving closer to awakening.
In It All Ends Now V, after Groudon and Kyogre's battle had been stopped, Groudon was revealed to have chosen 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.