In the fictional universe of J. R. R. Tolkien's Middle-earth, Caradhras, also called the Redhorn (the literal English translation of the Sindarin name), and known in the Dwarves' language as Barazinbar, is one of the mightiest peaks in the Misty Mountains. Tolkien indicated that it had a height of 17,500 feet (5,334 metres).
The mountain stands above the Redhorn Gate, the only known surface route through the Misty Mountains between Rivendell and the Gap of Rohan. Along with Celebdil and Fanuidhol, Caradhras is one of the three Mountains of Moria, beneath which the great Dwarf realm of Khazad-dûm was built. Below the snowline, Caradhras is described as having dull red slopes, "as if stained with blood", which is perhaps the origin of its name.
Caradhras is the northernmost of the three Mountains of Moria. The mithril mines, on which Khazad-dûm's wealth was founded, were gradually extended north under Caradhras. It was here that miners found Durin's Bane, the Balrog of Moria.
Caradhras has for centuries had an evil reputation, earning the sobriquet "the Cruel". Gimli says that Caradhras bore that name before Sauron was known in the area, and dislikes both Elves and Dwarves.
The Redhorn Gate originally linked the former Noldorin realm of Eregion in the west to the Dimrill Dale and hence the Vale of Anduin in the east. After Eregion was destroyed in the War of the Elves and Sauron, this pass was predominantly used by Elves travelling between Lórien and Eriador. The Hobbits used this pass on their migration to Eriador from the Gladden Fields. The Redhorn Gate is notoriously treacherous, being noted especially as the site of Elrond's wife Celebrían's abduction by Orcs. Later, the Nine Walkers' attempt to traverse the pass nearly ended in disaster in a snowstorm. Besides the storm itself they endured distressing noises from the wind as well as a barrage of stones and were very nearly trapped by suspiciously placed snowdrifts. Gimli especially, as well as Boromir and to a lesser extent Aragorn, attributed this combination of threats to the malice of Caradhras. In the Peter Jackson film the "fell voice" is Saruman speaking in Quenya, who exhorts cruel Redhorn to strike at the Fellowship while Gandalf pleads for Caradhras to sleep.
Caradhras is reminiscent (in form and meaning) of the Greek word χαράδρα (charadra), which means "mountain stream".