https://www.dndbeyond.com/sources/scag/the-sword-coast-and-the-north#Mirabar

Mirabar is a human city that rests atop dwarven caverns. On the surface, humans dominate the population, with some dwarves mixed in, and a handful of gnomes and halflings.

The uppermost level of the undercity is mostly dwarves, with some few humans. The mixing of races is due to convenience of trade, preference, or skill; just as some few humans like to mine, to imbibe strong dwarven drink, and to work underground, so do a minority of dwarves take to the open sky, doing dock work, or even manning and building ships.

The lower levels beneath Mirabar are all dwarven, as even the most dwarf-like human can live so deep below ground for only so long. Almost all of its citizens, regardless of race, honor Moradin and the dwarven gods, making Mirabar a dwarven city in spirit and ethics, if not entirely by population.