Oldcastle’s location has not been stated, although it may be in the wolfswood. The only members of the house to appear are Lord Ondrew Locke, an old man who does not seem healthy enough to make long journeys; Donnel Locke, who was one of the northmen captured at Green Fork; and Ser Mallador Locke, a ranger of the Night’s Watch.
Information about House Locke that reveals spoilers from the books.