House Mooton of Maidenpool is a vassal house that holds fealty to House Tully of Riverrun. They control Maidenpool, a port town near the border between the Riverlands and the Crownlands, on the Bay of Crabs.
To protect her identity, Arya Stark claims to be from Maidenpool whilst serving Tywin Lannister as a cupbearer at Harrenhal. Tywin catches her out in her lie when she cannot identify the sigil of House Mooton. Arya then claims to be from Barrowton in the North instead, and accurately identifies their sigil. Tywin is convinced.
In the books
In the Song of Ice and Fire novels, House Mooton are the rulers of Maidenpool and their motto is Wisdom and Strength. Their current lord is William Mooton.
- House Mooton at A Wiki of Ice and Fire (spoilers from the books).