Looking across the Abecean Sea from just south of Anvil
The Abecean Sea is a body of water to the west of Tamriel that sits between Cyrodiil, Hammerfell, Valenwood and Summerset Isle. The sea is encompassed by the Eltheric Ocean.
In Oblivion, only the eastern part of the sea is present; it is the sea into which the Brena and Strid rivers flow and lies to the west of Anvil. Going north from Anvil, the Ayleid ruin Garlas Agea borders the sea with the vampire filled fort Crowhaven nearby. Further north lies the Ayleid ruin Beldaburo.
There also lies a mysterious ship wreck up north in the Abecean Sea, at the mouth of the Brena River (map).