What is "beleriand"

In J. R. R. Tolkien's fictional legendarium, Beleriand was a region in northwestern Middle-earth during the First Age. Events in Beleriand are described chiefly in his work The Silmarillion, which tells the story of the early ages of Middle-earth in a style similar to the epic hero tales of Nordic literature. Beleriand also appears in the works The Book of Lost Tales, The Children of Húrin, and in the epic poems of The Lays of Beleriand.