Eynhallow (Old Norse: Eyinhelga) is a small, presently uninhabited island, part of the Orkney Islands, off the north coast of Scotland. Eynhallow lies in Eynhallow Sound between Mainland, Orkney and Rousay. It is 75 hectares (0.29 sq mi) in area.
There is no ferry to the island, although Orkney Heritage Society organises a trip each July. Otherwise, visitors have to arrange their own transport to the island by private local boat hire. Access can be problematic, as there are strong tidal surges in the surrounding strait, squeezed between Mainland of Orkney and Rousay.