Nan Elmoth was the forest in Beleriand east of Doriath and south of the River Celon. One of the two roads that the Dwarves took from Blue Mountains towards Beleriand passed near Nan Elmoth. There the trees grew to be the tallest and darkest in Beleriand, blocking the sun entirely from the forest floor.
Melian met Thingol in Nan Elmoth, before they founded the realm of Doriath. Years later, Eöl the Dark Elf dwelt there. Nan Elmoth was held to be part of Doriath, and Eöl paid Thingol with the black sword Anglachel as a fee for living there.