High Quality Content by WIKIPEDIA articles! The Organ Pipes National Park (OPNP), a 121 hectares (300 acres) protected area, is located in Victoria, Australia. It was established with the focus on conservation of the native flora and fauna, and preservation of the geological features in the Jacksons Creek, a part of the Maribyrnong valley, north-west of Melbourne. It is situated in a deep gorge in the barren Keilor plains.