Orod Certhas (S. "Rune Mountain") was the northernmost spire of the Bleak Mountains. The mountain got its name from a series of smooth, sloping cliffs of bare granite upon its northern face, graven with cirth, the runic characters of the Elves. The Noldorin Anustari of Evermist had once carved these inscriptions which, they said, recorded every spell that had ever been woven within Arda by the Firstborn. The Noldor did not reveal to others their reasons for having chosen so remote a site to enshrine the wisdom of the ages, but it was whispered among the wise that the bones of Orod Certhas were veined with the very power of the Earth. Whatever the truth of this, the Noldor undertook regular pilgrimages to the mountain, there to add new spells to its innumerable engravings. Doubtless many such enchantments were in reality banes for the protection of the mountain's inviolability. Neither the Orcs of Ered Muil nor the dragon Canadras had ever dared to defile the slopes of Orod Certhas.
The lower slopes of Orod Certhas were covered with snow from early autumn to mid-spring, while the rune-cliffs of the high places were snowbound year-round. The endless, slow workings of snow and ice occasionally cracked and damaged the rune-lines, which were typically between one and three inches in height. To reach the rune-cliffs of Orod Certhas, a pilgrim had to ascend the mountain's high and perilous escarpments. Ice and snow had to be cleared from the cliffside before the runes became legible, and not all the cliffs contained spells. The Noldor also possessed hidden refugecaves upon the mountain's slopes, without whose protection a climber, whether mortal or deathless, would have been destroyed by the spirits of wind and cold that assailed Orod Certhas by night.