Amon Ethir, also known as Spyhill, was an artificial hill in the plain of Talath Dirnen above the river Narog. Situated around a league (five kilometers) east of the Doors of Nargothrond, its clear summit was used by Finrod Felagund's spies to watch the surrounding lands.
The hill remaining standing after the Sack of Nargothrond and in these later years Nienor encountered Glaurung the Dragon here, who had blanketed the land with dragon-reek, with only the hill top above the mists. Here he cast Nienor into a deep spell of forgetfulness.
Amon Ethir meant 'Hill of spies' in Sindarin.