The town of Idrija lies in the
Idrija Basin, surrounded by the
Idrija Hills. It is traversed by the Idrijca River, which is joined there by Nikova Creek. It includes the hamlets of Brusovše, Cegovnica, Prenjuta, and Žabja Vas close to the town center, as well as the more outlying hamlets of Češnjice, Ljubevč, Kovačev Rovt, Marof, Mokraška Vas, Podroteja, Razpotje, Staje, and Zahoda. The Marof hydroelectric plant is located on the Idrijca River on the northern outskirts of Idrija, between Marof and Mokraška Vas. Springs in the area include Podroteja Spring and Wild Lake on the Idrijca River south of the town.