The Clayr's Glacier is a huge glacier at the North of the Old Kingdom, and is the most northerly location on Mogget's map. It is the ancestral home of the Clayr, and it said the purity of the ice focuses their Sight. The glacier itself runs between two mountain peaks: Starmount and Sunfall, and the Clayr's home is under the former. The glacier is the main focus of part one of Lirael, as the title character explores the labyrinthine Library. The Clayr's Glacier (like the Abhorsen's House) is protected by many unseen defences, Lirael explains that the River Ratterlin creates a barrier to the dead, and that there are wards, and sendings who protected the Glacier.