Pendragon Castle is in Cumbria, four miles south of Kirkby Stephen. Local lore links this castle to King Arthur's father, Uther Pendragon. The only mention of Pendragon Castle in King Arthur literature is in Thomas Malory's Le Morte D'Arthur of the fifteenth century, and no clues are given as to its location.
The present Pendragon Castle is a Norman castle built by Hugh de Morville in the 12th century. Hugh is one of the knights who assassinated of Thomas á Becket. It sits on a small mound in a field east of the River Eden. Surrouding this mound is a ditch, perhaps 15-20 feet deep which forms a horseshoe shape around the castle
One story tells of how Uther was killed here at Pendragon Castle with one hundred of his men when Saxon dogs poisoned the well. Another relates Uther's attempt to divert the nearby River Eden to create a moat for this castle.
Any King Arthur connection with Pendragon Castle appears to be tenuous
Northern England Arthurian Sites