Tagmeth is a ruined northern Riverland keep, on the eastern bank of the Silver. Tagmeth is also the title of P. C. Hodgell's livejournal blog. It is possible that Tagmeth keep will be restored in the future, given that in "Stranger Blood"—a short story that is set later than any of the novels—contains a Highborn named Kracarn of Tagmeth. It looks like The Gates of Tagmeth with entail that.