The Mountains

The Valley should not exist. The science of plate tectonics, which is currently beyond the inhabitants of The Valley's world, does not allow a piece of land that sits 500 feet above sea level and boasts an area of nearly 50,000 mi² to exist in the center of a mountain range nearly 4 million mi². The land should have been crushed into mountains as the supercontinent was formed, creating this enormous mountain range.
Something kept The Valley protected as mountains rose around it, creating a nearly impenetrable maze of mountains that stretch over 15,000 feet above sea level and fill the north-central portion of the supercontinent.

Geography

On the furthest reaches of the mountain range, you will find the typical system of foothills, ridges, steppes, and lakes. There are many inhabitants that make these areas their home. However, the mountains quickly become inhospitable the further into the range you travel. After a week's travel, the common cycle of mountain peaks, passes, and streams running through small mountain valleys gives way to steep crags, sudden cliffs over 1,000 feet high, and perpetual snow and ice. If there are valleys, they are choked with Alpine Glaciers.
There are rivers, fed on snowmelt and glaciers, that wind their way through the mountains, but none have successfully traversed up their treacherous waters. As the mountain range continues, seemingly without end, precipitation slowly decreases. There are regions of the mountains that are a dry as a desert, having never seen rainfall.
However, this is quite different in the Valley. Instead of foothills and steppes, the border of the Valley is defined by a literal wall of stone that rises from the ground. It was almost as if the mountains were unable to grow out of the land of the valley, causing mountains to form cliffs rising 5000 feet into the air. In some places, these cliffs lean out over the valley for hundreds of feet, causing dangerous areas of rockfalls.
In some places, streams of water trickle from the cliffs themselves, but in most areas, water plummets from the clifftops, falling thousands of feet. While some of this water does fall onto the land, most becomes mist and forms clouds, eventually falling as rain further into the Valley.
There are a few places where the mountains crept further into the valley, creating foothills and, most importantly, passes into the valley. Without these passes, the refugees would have been nearly impossible to find a way into the Valley.

The Lake Pass

The least useful of the passes, this one is located and only accessible through ships traveling across the Great Lake. It is made up of about three miles of foothills descending from a pass about 2,000 feet above the lake's surface. A small collection of Mountain Scout guards are posted here, as well as a few Animal Gifts attempting to domesticate the stubborn and incredibly strong Valley Bison in an area where the creature can't escape.

The Eastern Gate

The Eastern Gate is the largest pass, nearly a mile wide at one point, and multiple potential paths branch out from the pass. Many Mountain Scouts guard this pass.

The Southern Pass

A small pass, the pass the refugees found that allowed them to enter The Valley.

The Wastelands Cleft

A unique opening into the mountains, the Wastelands Cleft is a crack in the mountain wall through which a river flows. There are long switchbacks along the crack that lead up into the mountains. There are a few mountain scouts guarding this area, but during Spring and early Summer the area is impassible due to flooding from melting ice and snow.

Fauna & Flora

Mountains are challenging places for life to survive, but many plants and animals manage to eke out an existence. Most of these are avian, as well as a collection of small rodents. However, there are several species of larger mammals that live in the mountain range.

Fauna

Flora

Natural Resources

Having direct access to the "heart" of a mountain through the cliffs allows miners a unique opportunity. With full access to veins of stone, ore, and coal, mining is surprisingly easy. However, working that close to the Cliffs is a dangerous task, and several miners are killed every year by falling stones.
Some spend the summer harvesting ice from frozen mountain lakes and transporting the blocks down to the valley floor.

Type

Mountain Range