The name used only for military organization of the East of Rohan. The East-mark included all of the lands east of the Entwash and the Snowbourn rivers. Here a Marshal of the Mark was the chief military commander and he typically made his home at Aldburg in the Folde. For a time during the War of the Ring, the East-mark was charged to the Third Marshal of the Mark, √Čomer son of √Čomund.
Encyclopedia entry originally written by Nienna-of-the-Valar