Eastwatch-by-the-Sea is one of the nineteen Night's Watch military fortifications established along the Wall, and one of the three fortifications that is still operational by 280 AC. It is the easternmost castle along the Wall, located on the coast of the Bay of Seals, with Greenguard to the west. The castle freuqently trade with wildlings, and protects the eastern end of the Wall from threats trying to get around it. In the show, following the Battle of the Bastards, King Jon Snow sent wildlings to reinforce the castle's garrison.