The Rainwood is a great forest in the Stormlands.
In the books
In the A Song of Ice and Fire novels, the Rainwood is a large forest that lies on Cape Wrath in the Stormlands. Although it is rainy, the region is fertile enough. Mistwood is located in the southern rainwood, while Rain House is found in its northeast.
In A Storm of Swords, Ser Dermot of the Rainwood is pardoned by King Joffrey after the battle of the Blackwater.
Davos Seaworth, when proclaimed Hand of the King to Stannis Baratheon, also gained the title Lord of the Rainwood.