Ryn’Alar, the Great Human Kingdom.
Founded centuries ago, Ryn’Alar was initially a collection of like-minded city-states. Forced to defend against constant incursions from monstrous warbands emerging from the Old Kingdoms, the separate governments began to unify into a common land.
Perhaps because of their initial struggles, Ryn’Alar became phobic regarding many of the other races. Though they might accept the more humanoid species, every King has been a pure-blooded human. All the high-ranking military and diplomatic positions are held by Human families with the purest pedigree and the idea of intermarrying with other races is anathema to Alarians of all social standings.
That said, a few races have gained enough favor with the Alarians to be considered almost human. Dragonborn are considered excellent warriors and can advance very far in the Alarian military, with some near-legendary examples reaching as far as general. Elves and dwarves are praised for their craftmanship and knowledge of the wilds, though their presence is seen as less and less necessary as civilization encroaches further and further into the wilderness. Halflings and gnomes have gained tolerance if not acceptance, simply by being underfoot constantly enough that most humans hardly notice their existence.
A few other races have managed to integrate themselves as well, but most are limited to specific regions rather than the kingdom as a whole.