The Sunset Sea is the great, unexplored ocean lying to the west of Westeros. Numerous explorers have sailed into the Sunset Sea searching for new lands, but save a few small islands located several weeks' travel west of the Iron Islands, nothing has been found, or at least no explorers have returned home alive to talk about it.
In the books
In the A Song of Ice and Fire novels, the Sunset Sea is considered vast and uncrossable, though some ironborn claim to have found more substantial land in the far west. These claims are usually disbelieved.
The most famous explorer of the Sunset Sea was King Brandon Stark (the unknown number of his line), who sailed west with the most of the Northern fleet to find new lands and was never seen again. His son, Brandon the Burner, burned the remaining ships in grief and fury. The North has had no significant strength at sea since this time.
See also
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