A reservoir in Glen Affric, Loch Beinn a' Mheadhoin lies 1¼ miles east of Loch Affric and 13 miles northwest of Fort Augustus. Part of the Affric-Beauly Hydro Electric scheme, the loch receives water by tunnel from Loch Mullardoch to the northwest. It extends 5½ miles northeast to terminate at the Benevean Dam. From this dam the River Affric issues, but water is also diverted to the generating station at Fasnakyle.