Siril was the greatest of the few rivers on the island of Númenor. It rose in the valley of Noirinan beneath Meneltarma, and flowed directly southwards to enter the sea at the fishing port of Nindamos, on the borders of the Hyarnustar and the Hyarrostar. In its lower course it became a slow and winding stream, meeting the sea among wide marshes and reedy flats.
