This subterranean city bears the same name as the country it is located in. The city is built in layers, going ever deeper with the growth of its population. It is very rare that any visitor goes beyond the surface level of the city, though that is located in a cave system inside the mountain as well.
A lot of places in deeper levels don't take account of the taller races since the population is mainly made up of dwarves and gnomes. As such there are areas which taller races would have to bend down or even crawl to get through. On the surface level there are buildings such as shops, inns and taverns that are built specifically to accommodate larger races.
Hilboldir is run by a council made up of people living on each level of the city. Each person is elected by the people living on the same layer. The council meets every week to discuss what has happened on each layer, if anything needs to be changed or fixed and concerns that have been brought to the council members by the civilians. These meetings can take several hours and be so loud that they echo throughout several caverns - not always because of anger but of other strong emotions.
Defences for the surface level are minimal, relying on a gated entrance and some guards. For the deep layers of the city, however, having strong defences is of the utmost importance with natural cave systems leading to the Underdark. All known paths or weak points where creatures from the Underdark can break through are heavily guarded at all times of the day. Druids are very valued as they can manipulate the stone, both as quick stop gaps and overtime to make it stronger.
The main industry and trade come from metals and gemstones which are mined deep in the mountains.
Skilled blacksmiths and tinkerers export their work and there is no other place to buy weapons and armour with such high quality in Aporea.
The main import is produce of all kinds.
During the first years of the Age of Parting, dwarves felt uprooted. Gone were their carefully mined and crafted cities under the surface. Suddenly they stood out in the sun and they did not like it at all. So when a few dwarves found a natural cave system in the mountains of Hilboldir it didn't take long for many others to follow. The more natural and ramshackle nature of their new home was a bit discouraging but they were soon finding hidden gems in the rough, quite literally.
Perhaps Hilboldir has never reached the beauty and refinement that their old cities had during the Age of Creation but it is a home and a valuable one at that. Still, thousands of years later, the mountain gives them precious materials and stones.