Beleriand is the fictional land where many of J.R.R. Tolkien’s First Age stories take place. It was a region in the western part of Middle-earth, bordered by the Blue Mountains to the east and associated with major events in The Silmarillion.
Beleriand was the setting for the wars between the Elves and Morgoth, the first Dark Lord. Important places there include Doriath, Gondolin, Nargothrond, and the havens of the Falas. The stories of Beren and Lúthien, Túrin Turambar, and the fall of Gondolin are all connected with its history.
At the end of the First Age, the War of Wrath reshaped the region. Much of Beleriand was destroyed and sank beneath the sea, leaving only limited eastern areas connected with later geography. It is therefore not the same region as Eriador, which is prominent in The Hobbit and The Lord of the Rings.