The Rangers of the North were the last remnant of the Dúnedain who had once peopled the North-kingdom of Arnor. They were led by a line of Chieftains, each of whom could trace his descent back to Isildur himself.

After the fall of Arthedain in TA 1974, the Heirs of Isildur passed into the shadows, emerging only later as wandering rangers whose true identity was unsuspected by the inhabitants of Eriador, where they spent most of their days. They took upon themselves the task of protecting the Northlands, working quietly and in secret.

The Elves of Rivendell, however, were privy to the tasks of the Dúnedain, and the Eldar of Rivendell often rode with the Rangers on their missions. But the dwellers of Bree and the Shire were unaware of the Dúnedain guardianship of their lands.

The first Chieftain was Aranarth, the son of Arvedui - the last King of Arthedain. At the time of the War of the Ring, the Chieftain of the Dúnedain was Aragorn, but the people he led were scattered and diminished. When Halbarad led a troop of the Rangers into the south to Aragorn's aid in the War, he could muster no more than thirty for the ride.

The term 'Rangers of the North' was used to distinguish the Northern Dúnedain from their distant cousins, the Rangers of Ithilien. Like the Rangers of the North, these were also Dúnedain, but they belonged to the South-kingdom of Gondor, and their ancestors had been divided from the Northern Dúnedain for some three thousand years.
Encyclopedia entry originally written by atalante_star