Dunharrow was a refuge of the Rohirrim hidden in the White Mountains and fortified against attack. Dunharrow had been used as a refuge by the Middle Men of the White Mountains during the Second Age — nearly three mellennia before the establishment of the Kingdom of Rohan.
Dunharrow was a clifftop overlooking Harrowdale, the valley of the river Snowbourn. In order to reach the refuge, a winding path had to be used, known as the Stair of the Hold. This path was lined with statues known as the Púkel-men — statues originally carved by the Men of the White Mountains, in the likeness of the Drúedain. After the stair was the "Firienfeld", a large grassy area for the encampment of soldiers and refuge-seekers.
Tolkien made Dunharrow the modern form of Rohan (Old English) Dūnhaerg, meaning "the heathen fane on the hillside".1