Aglon (S.: "narrow pass") was a pass into Beleriand from Lothlann between the hills of Dorthonion and Himring. Aglon was fortified by Celegorm and Curufin, but the pass was forced by Morgoth's armies during Dagor Bargollach. Maedhros soon retook Aglon, but when he fled from the north after the Nirnaeth Arnoediad the pass was left undefended.