The Frigid Arboretum (The Fridge) 

The area of the Underground directly  beneath the glacier aboveground, The Fridge is constantly in various states 

Winterrest

The capital of The Fridge, encircling the highest point in the Underground and capped off with the University of Higher Magical Proficiency. A winter wonderland comprised of decorative cabins, shops, and various wintertime attractions. Atop the highest tower rings an ancient bell, audible all across the Underground. Overrun by ice spiders, frozen variants of the spiderfolk that live deep in the caverns of Hotland.

The Deep Woods

The large forest that covers more than 3/4ths of the Fridge. Once a source of livelihood for many monsters, it now stands as not just refuge and camouflage to the many rabid beasts prowling within, but as a danger in and of itself. The trees in several places have awakened, just as hungry as the monsters that stalk through them, and have been seen not just attacking monsters, but slowly moving across the ground.

Lumberton

A sawmill, wood processing plant, and small village located at the heart of the Deep Woods. Long abandoned, and used as Greater Dog’s den; decorated with many skulls, the dust of fallen monsters, and the giant, twisted dog monster’s claw marks. 

Ferron

A town settled at the base of the Cold Iron Cliffs, where the workers of the nearby mines rested from their labor. The mines provided a great deal of the iron and stone the kingdom required for its infrastructure. The town had attempted its own quarantine, before a ravenous dragon monster moved into the mines and slowly picked them off, one by one. It now stands barren, though the dragon emerges from time to time to search for prey.

Aerie

A city built into the side of the mountain that houses a great deal of the kingdom’s winged and floating monsters, only accessible through the ability of flight. Most of the Underground’s air elementals called this place home, and from its peaks the mail service was run all through the kingdom, along with numerous transportation systems and courier services. No one knows what became of the monsters high in their nests, but none have emerged since the Hunger took hold.

The Crystal Castles

The ancestral home of the water and ice elementals, a series of intricate, beautiful, and legendary ice castles set at the northmost section of the Fridge. They oversaw the cleanliness of the rivers and lakes of the Underground, once upon a time, but a few years after the Hunger had overtaken the kingdom, the castles shattered and fell to pieces, slowly poisoning the Great River with dust. 

Snowdin

A small trading village, and Royal Guard outpost, set at one of the main crossroads of the Fridge, and home to the machine that is responsible for cooling the CORE in Hotland. The machine has long ceased to function, contributing to the damage the CORE has taken. The village has been completely cordoned off, and surrounded by traps, by Sans and Papyrus, a stronghold against the elements and enemies both.