Realm in northern Middle Earth (JRR Tolkien's world), the original home of the people who later became the Rohirrim. The word was used to refer to both the realm and the people. The people moved to Rohan and became the Rohirrim after aiding Gondor at the Battle of the Field of Celebrant and being granted the province of Calenardhon (Rohan) as a reward. Eotheod is also the place of origin of the mearas, the great horses of Rohan.
Marked on maps in the Lord of the Rings, but never figures in the book. The War in Middle Earth PC game has tastefully sited a number of ruined towns and an important artefact in the region.
Eotheod is south of Mount Gundabad, north of the realm of the Beornings and east of the Misty Mountains.
Eorl led the Eotheod people from Eotheod to Rohan.