Buk National Park is a national park in the Buk Mountains in northern Hungary near Miskolc. It was established in 1976 as the third national park in the country. With an area of 431.3 km², it is one of the largest national forests in Hungary. Boc's important geological features include the various karst formations within its limestone mountains, such as caves, boulders and valleys. It also includes the country's longest cave, Istvánlápa, and contains ninety species of nesting birds, some of which are considered endangered.