The Westerlands are the Westerosi lands to the west of the Riverlands and north of the Reach. They are ruled by House Lannister of Casterly Rock, formerly Kings of the Rock. People of this region are often called "Westermen." Lannisport, lying hard by Casterly Rock, is the chief town of the region and one of the great ports and cities of Westeros. The Westerlands are rich in precious metals, mostly gold, which is the source of their wealth. Keeping with Westerosi customs to give bastards a surname showing their origins, illegitimate children born in the Westerlands are given the surname Hill.