The City Watch of Lannisport is one of best trained in the world and keeps the city running efficiently.

The Lannister fleet is one of the finest on the Sunset Sea and was built to withstand naval attacks from the Iron Islands. The city boasts one of the major ports of Westeros, attracting trade from all over the known world. Three of the major roads of Westeros (the River Road, the Gold Road, and the Ocean Road) connect Lannisport to the surrounding regions. The Lannisters improved the harbor, built the walls and gatehouses, and managed the finances of the city, which grew rich from several gold mines and goldsmiths in the area. The city's expansion was managed by House Lannister, the Kings of the Rock after they claimed Casterly Rock from House Casterly in the Age of Heroes. The ancient city was first a village, then a town, first built at the base of Casterly Rock but has grown into a center of trade, finance, and military strength. Lannisport is one of the major cities of Westeros, and is the third largest after Oldtown and King's Landing. The crescent moon is highly symbolic for House Arryn and connected to the name of the mountain range in the Vale, 'The Mountains of the Moon,' their castle on the valley floor, 'The Gates of the Moon,' and their method of execution, 'The Moon Door,' a door on the side of their great hall from which people are thrown and plunge six hundred feet to their deaths on the rocks below. The sigil of House Arryn is a falcon volant next to a crescent moon. Some notable members of the house are Jon Arryn (previous Hand of the King), Lysa (Tully) Arryn (Catelyn's Sister), and Robert Arryn (Son of Jon Arryn and renamed Robin in the show for there being too many Roberts.). The castle is described as '7 white swords thrust into the belly of the sky' and is considerable impregnable because of its location and defenses. The Eyrie proper is a castle that is nestled at the peak of the Giant's Lance, the largest mountain in all of Westeros. House Arryn of the Eyrie, being one of the most influential houses in Westeros, is the principal ruling house of The Vale of Arryn.

Houses of the north westeros