The oldest of the great powers of Lunistria, the Elven pepole collectively rule a territory roughly the size of Brazil, Bordered on two sides by the Eastwall and Northwall mountains, to the south by a range of “hills” that Georgians might mistake for the Appalachians, and to the East by the ocean. With the exception of the sea, none of these features appeared naturally in their current state. Blame the High Kings.
The climate of Elfland (as outsiders frequently call it) is generally a pleasant, temperate environment, until the Elves decide to be “artistic” about it. The region is insanely prosperous, given how little “work” appears to be performed at a day-to-day level, but when you live for centuries, you tend to get good at things.
Most of the people in the Principalities are Elves, directly ruled by and related to one of the Great Houses, or possibly part of the High Elven line. This isn't to say there aren't non-Elves here: there are small populations of other races scattered about in carefully managed clusters, not quite slaves, but clearly second-class citizens in the Great Scheme of things. They generally perform specialized tasks that the Elves find either beneath them, or are too complicated to “just throw magic” at.
Unlike the Aelves of the original Crosswinds campaign, the current generations are not hard-coded to specific, elemental magical schools. The Great Houses do specialize, yes, but that is a deliberate cultural decision, not Divine Fiat. Also, non-noble-born Elves frequently lean magics outside the House styles.
The history of the Principalities as a cohesive political entity begins all the way back during the Divine Era, when a wandering Elf named Regis masterd the occult, martial, and marital arts, had countless adventures, slept with a sizable fraction of the mortal and immortal ladies on the planet, and proved to be an insurmountable pain-in-the-arse to the rulers of the varying Even tribes. Out of a sense of frustration, they ended up telling him that HE was now in charge, regrouped in what would become their modern borders, and set about making it their own.
Fortunately for the people already present, Regis wasn't as much of a jerk as his new Princes were. Most of the non-Elves made out in reasonably good shape, if not unreasonably upset with the Elves in general. Regis I wasn't a bad ruler, but if he had a weakness, it was an inability to delegate. His daughter, Gloriana had no such issues, and took the reigns when her father perished fighting something he should have sent an army after, at a symbolic age 400.
Up until the current holder of the title, Regis was the only High King to live that long.
At the low level, the economy of Elfland is fairly ordinary, if a bit more barter based than in other lands. It is when you reach the level of the gentry that you realize the entire place is run on quid pro quo, and “money” is just a convenient, if barbaric, token to keep score with. This may drive outside traders to frustration, but as long as the Elves want outland luxuries, and the gold keeps flowing, they cope.
The Merchant's Guild does not have a presence in the Principalities outside of border and coastal regions. The Mercenaries Guild is more widespread, particularly around the Kingsmere.