The Skill and The Wit (spoilers all RotE books)

['thul]

Elderlings did have at one time habitation all the way to the coast of the duchies, but that part was ancient.

Elderlings did document their history, but not on paper/parchment. They recorded it in the walls of their cities and in memory stone cubes. After all, why record knowledge meant to last centuries on something that decomposes, when you can more easily and permanently record it in stone?

Evidence in the realm of the Elderlings says that Elderlings passed out of existence several centuries ago, and that they had been fairly common for millennia before that. A human in RotE society can live for say, 70 years. Elderlings can live something like 3-4 centuries... Dragons live for at least a few thousand years. For Elderling lifespan to have been so recorded as fact, there would have had to be dozens of generations of Elderlings, at least. That would put the draconic era into at least covering something like 50,000 years... Having a city in a single place is rarely upheld for even a fraction of that time...

That series of timeframes indicates that while Elderlings once inhabited Buck, they had probably abandoned that region long ago... Also, the pillars were used only for emergencies, even by Elderlings. As for the pillar Fitz came through in the end, yes that one is close. It is known as one of the wisdom stones.