In J. R. R. Tolkien's legendarium, the Rangers of the North, also known as the Dúnedain of the North, were the descendants of the Dúnedain from the lost kingdom of Arnor. Their menfolk ceaselessly patrolled the boundaries of Eriador and were by necessity skilled with the sword, bow, and spear.
The Rangers were grim in life, appearance, and dress, choosing to wear rusty green and brown. The Rangers of the Grey Company (see below) were dressed in dark grey cloaks and openly wore a silver brooch shaped like a pointed star during the War of the Ring. These Rangers rode rough-haired, sturdy horses, were helmeted and carried shields. Their armament included spears and bows.
Like their distant cousins, the Rangers of Ithilien, the Rangers of the North spoke Sindarin (or some variation of it) in preference to the Common Speech. They were led by a Chieftain, whose ancestry could be traced back to Elendil and beyond, to the ancient Kings of Númenor.
During the War of the Ring, the Rangers of the North were led by Aragorn, but the northern Dúnedain were a dwindling and presumably widely scattered folk: when Halbarad received a message to gather as many of the Rangers as he could and lead them south to Aragorn’s aid, only thirty men (the Grey Company) were available at short notice for the journey. The Grey Company met up with Aragorn, Legolas, and Gimli at the Fords of Isen in Rohan, and at Pelargir, along with the Dead Men of Dunharrow, they captured the ships of Umbar. The Dead Men then departed and the others continued on to fight in the Battle of the Pelennor Fields. There, Halbarad was killed. They are also mentioned as part of the army Aragorn commanded at the Battle of Morannon.