Giants

Giants are a non-human sentient race, considered legendary by the inhabitants of the Seven Kingdoms south of The Wall. However, many Wildings living north of the Wall claim that they have encountered them, in the regions of the farther north of the Lands Beyond the Wall.

In the Series
Osha the Wilding asks Bran Stark if the unusually tall Hodor has some giant's blood in him. Osha insists that Giants actually do exist north of the Wall. ("The Pointy End").