Dwarflands

The Dwarflands are a mountain range to the north of the Valley. They're made up of 3 separate mountain ranges; the Stoneheart Mountains (which give The Valley its name), as well as Dwerfater's Crown, and the Reach.
The Dwarflands are home to two very different civilisations. Below the mountains are the "deep" or "hold" dwarves, who are pretty familiar. They mine for minerals, build grand halls and are generally extremely wealthy.
Holds go through a very linear life cycle. First an area is found with some running water and a few likely-looking cliff faces. A few enterprising dwarves will set up some small farms to allow themselves to be self-sufficient while they prospect. If good minerals are found, more dwarves will arrive and the settlement will become a mine. Depending on what's found, jewelers, artisans or smiths may show up to make use of the raw materials. As the hold expands, mining may play a smaller role as craftsdwarves and other professionals like shopkeepers come to make up the bulk of the economy. Here a hold may sit for centuries, producing some reasonable amount of raw materials while craftsdwarves do Dwerfater's work by making beautiful crafts. Trade brings in more coin all the time, and since holds need to import very little (often only wood and food), wealth accumulates. Holds don't trade with the Valley much; the Valley has little the holds need, and is usually too poor to afford any of the holds' crafts. Most trade is with the Sands, or with Lundar. Lundar is an especially important partner, as they have little to no access to mithril, but is the source of nearly all the Valley's adamantium. There's some trade with the Underdark, but the nature and volume of it remains a mystery.
Eventually a hold will run out of raw materials. In most holds this doesn't matter, there is enough wealth for dwarves to spend their time as they please. Eventually, younger dwarves will leave for new adventures, and the cycle begins anew. 
The Hold Dwarves are not what they once were. There are plenty of remnants, from the 4th age, of times when things were better: works of art on an unimaginable scale, and complicated smithing. Massive tunnels connected major holds, called the Deep Roads, although all bar a few of these are collapsed, flooded or infested with monsters. Some are still in use, with great "trains" of iron that burrow through the ice for those who want to cross the dwarflands in the fastest and most exciting way possible.
In the snowy peaks high above the holds live the other civilization: The Mountain Dwarves. Mountain Dwarves are weird. They live on peaks with magma and snow, surviving by hunting and scavenging. They have a high number of barbarians and sorcerers, and are highly xenophobic. Anyone coming into their territory is considered fair game, and are often attacked without warning. The Mountain Dwarves have also domesticated a few flying mounts, such as a powerful breed of snowy griphons, ice drakes, and other stranger things. For this reason, few travellers choose to fly across the mountains; most instead pay the heavy tolls to travel though the holds.
With access to the coldest ice as well as magma, the mountain dwarves are home to the best smiths on the continent, if not the planet. It's something of an embarrassment to the hold dwarves, but mountain dwarves can turn what little ore they have access to into the finest of steel and mithril alloy. 
The mountain dwarves are something of a concern, as no one is sure how many there are, how well organised they are, or why they very rarely conduct raids outside of their normal territory. 
There are a few non-dwarven settlements in the Dwarflands as well. Some are just small towns of people who like the mountain air, and others are trade hubs. One of the largest of these is Griefnir, a powerful city on the east coast. It's the last port of call for many ships before they cross to Lundar, and is home to a powerful noble family that was once an ally of Lycia.