Eastemnet
From Tolkien Gateway
Eastemnet is the wide land of Rohan east of the River Entwash until the Anduin, the easternmost land of the kingdom.
There were few fixed settlements here, but many of the herdsmen of the Rohirrim lived a nomadic existence on the fields of the Eastemnet, living out of temporary camps and driving their herds across the grasslands.
Etymology
Emnet means "plain".