Our town's fallen quiet you see. The other residents, they've all disappeared. Headed down that well, one by one, into the caverns below.
Dirtmouth is the first town on the way to Hallownest, located in the valley between the Howling Cliffs and Crystal Peak. In Hollow Knight, it initially has only one resident, but more bugs can return or move into town depending on certain events.
Dirtmouth is located right above the ruins of the kingdom of Hallownest, in a barren valley with rare tufts of grass, safe from the winds of the wasteland. Many lumafly lamposts are erected in and around town. Travellers used to come through the King's Pass, west of the valley, during the kingdom's heyday. However, a large door now bars access to the pass and the bridge leading down from it collapsed, forcing the occasional wanderers through hard detours around the cliffs. The Knight reaches Dirtmouth through that pass after breaking down its stone door, marking the start of their journey through Hallownest.
Dirtmouth itself is almost abandoned, with many of the houses boarded up and empty. Elderbug is the oldest remaining bug in town and the only remaining resident. Bretta and Sly, two of the missing residents, return to town if they are rescued, with Sly resuming his job as Dirtmouth's shopkeep.
Besides a shop, Dirtmouth also has a Stag Station locked from the inside but reachable from any other Station. Iselda opens a map shop next to the station when a Map has been purchased or False Knight has been defeated.
East of town is a graveyard which leads to a stone door barring a cave, requiring a Simple Key to open. Confessor Jiji can be found in that cave in normal mode, or Steel Soul Jinn in Steel Soul Mode. Above the door, a lift goes up to Crystal Peak, but the lever to activate it is by the mines' entrances.
Dirtmouth used to be a bustling town during Hallownest's golden age, being a respite for travellers to and from the kingdom. They would reach town through King's Pass, then either head down the kingdom's roads by foot or by Stag or head straight to the crystal mines by a mechanical lift.
Once the Infection spread across Hallownest, all entry points into the kingdom were sealed to prevent the spread of the Infection, including the Stag Station. Dirtmouth's old well remained as the only way to enter Hallownest. Over the years, this well was used by many wanderers and adventurers to get into the ruins of the kingdom, with few of them ever returning. When the bridge up to King's Pass crumbled away, the few travellers coming to Dirtmouth had to take circuitous routes around the cliffs.
Over time, nearly everyone living in Dirtmouth went down the well, drawn in one by one by the promise of wealth, glory, or enlightenment. The town fell quiet, with none of the residents ever returning from the ruins of Hallownest.
How to access
The initial way to access Dirtmouth is from King's Pass, after breaking down the door at the very end of the area.
Sub-area: King's Pass
King's Pass is a set of desolate tunnels going through the cliffs west of Dirtmouth. It used to be the main entryway into Hallownest, but fell into disrepair, forcing the occasional traveller to circle around the cliffs. The caverns' walls are covered with giant fossilised shells and contain glowing Lore Tablets throughout the ruined road. At the far east is a large sealed door that must be broken open to access Dirtmouth and the rest of Hallownest.
This area can later be returned to through the Howling Cliffs, or by going back through the eastern entrance using the Mantis Claw or by using Crystal Heart from the most western point of Crystal Peak.
The Grimm Troupe's Tents
After the Grimm Troupe's Quest has been started, two large tents appear in Dirtmouth, shocking its inhabitants. The smaller tent is home to Divine, who can turn Leg Eater's Fragile Charms into Unbreakable ones, for a large amount of Geo.
The larger tent contains a grand stage in which Grimm offers the Knight a Charm, Grimmchild. This tent also hosts Grimm's fight. After this fight and once all flames have been collected, an area to the right of the stage opens up. At the end of a long corridor, Grimm can be found sleeping. With the Grimmchild Charm equipped he can be Dream Nailed in order to start the Nightmare King Grimm battle.
The eastern corridor of Grimm's Tent also contains a passage leading to a secret room. It can be accessed by climbing up the second arch from the left. The secret room has several inaccessible chests, the masks of the Grimmkin, and an unknown device in the middle. If a Spell is used in this room, a red barrier lights up.