One of the geographic sites which is commonly listed as King Arthur's Round Table is this formation at Mayburgh, near Penrith at the base of the Cumbrian Mountains. Originally this was a ritual site which Leslie Alcock dates to the third or early second millennium B.C.
Although some speculators consider this site too far north and outside the realm of conflict during the era of the historic King Arthur, it fits the theory that some of King Arthur's enemies were Saxon sympathizers from the north.