The mountain where the Fellowship of the Ring tries to cross is Caradhras.
Caradhras is one of the three peaks of the Misty Mountains above the Redhorn Pass. In The Fellowship of the Ring, the Fellowship attempts to cross the pass but is driven back by a severe snowstorm and falling snow, which makes the route too dangerous.
The failed crossing leads the company to consider the Mines of Moria instead. In Tolkien’s narrative, Caradhras is also associated with hostile supernatural forces, although the characters debate whether the mountain’s malice is literal or whether the storm is natural.
Caradhras is sometimes confused with Mount Doom, the volcano where the One Ring must ultimately be destroyed. Mount Doom lies in Mordor, while Caradhras is part of the Misty Mountains in Eriador’s eastern region. The name is also translated as “Redhorn.”