Trnovačko Lake (Trnovačko jezero) is a lake beneath the heights of Mountain Maglić, best known for its heart-like shape. Located at an altitude of 1517 metres, it is popular with local summer campers. It is 700 metres long and 400 metres wide, and set amidst a "huge amphitheater of rocky peaks". The lake drains from Maglić, the Maja e Vjelakut and the Bioč hill ranges. The lake water has a deep green-blue colour.
Maglić is the highest peak of Bosnia and Herzegovina at an elevation of 2,386 metres. It lies within the Sutjeska National Park.