The Hill-trolls were a race of Trolls adapted for life among hills and moorland. Aragorn's grandfather Arador was slain by them in the hills north of Rivendell, and a company of Hill-trolls were among the armies that Sauron loosed from the Morannon during the War of the Ring.

They were fearsome and vicious in battle, bellowing like animals as they engaged in fighting. They beat their enemies down with great hammers. In appearance they were man-like, but larger, and seem to have been covered with hard scales.