Hill-men were a race of Men historically descended from the mountain tribes of the White Mountains, who spread northward across Middle-earth during the Second Age. The Dunlendings and the Men of Bree were of this stock, as were Oathbreakers who marched with Aragorn in the War of the Ring.
During the Third Age the Hill-men were to be found near the Angle or the Ettenmoors. In the Angmar wars, Hill-men from Rhudaur allied themselves with the Witch-king and in T.A. 1350 usurped the throne of Rhudaur, sending the Dúnedain fleeing to Cardolan and Arthedain. The Kingdom, allied with Angmar against the other two kingdoms.
The Hill-men were later wiped-out during the Battle of Fornost, except for those who lived in Bree and the surrounding area.