The Blue Mountains National Park is a protected national park that is located in the Blue Mountains region of New South Wales, in eastern Australia. The 267,954-hectare national park is situated approximately 80 kilometres west of Sydney, and the park boundary is quite irregular as it is broken up by roads, urban areas and inholdings. Despite the name mountains, the area is an uplifted plateau, dissected by a number of larger rivers. The highest point in the park is Mount Werong at 1,215 metres above sea level; while the low point is on the Nepean River at 20 metres above sea level as it leaves the park.
The national park is one of the eight protected areas that, in 2000, was inscribed to form part of the UNESCO World Heritage–listed Greater Blue Mountains Area. The Greater Blue Mountains was one of 15 World Heritage places included in the National Heritage List on 21 May 2007. The Blue Mountains National Park is the most central of the eight protected areas within the World Heritage Site and it forms part of the Great Dividing Range.