Potkobiljak is located in the municipality Fužine, in Primorje-Gorski Kotar County at an elevation of 701 meters above sea level and it covers the area of 5.76 km² (2.22 sq. miles). Nobody lives in Potkobiljaku anymore. Nearby places: Lič, Banovina, Pirovište, Fužine, Vrata, Benkovac Fužinski, Tribalj Gornji, Tribalj, Zlobin and Drivenik.