Barrowfield
From Tolkien Gateway
The Barrowfield was a field outside the wall and dike of Edooras where the Rulers of Rohan were buried. By the end of the Third Age there were two rows of tombs: one for the First Line (Eorl to Helm Hammerhand) and one for the Second Line (Frealaf to Theoden). Simbelmyne grew on the western side of the mounds, and more thickly on Helm's.
It is not known if the Kings of the Third Line (starting with Éomer) were still buried there.