The Puerto Princesa Subterranean River National Park is a protected area of the Philippines located about 80 kilometres (50 mi) north of the city centre of Puerto Princesa, Palawan. The river is also called Puerto Princesa Underground River. The national park is located in the Saint Paul Mountain Range on the western coast of the island. It is bordered by St. Paul Bay to the north and the Babuyan River to the east. The City Government of Puerto Princesa has managed the National Park since 1992. The entrance to the subterranean river is a short hike or boat ride from the town Sabang.
In 2010, a group of environmentalists and geologists discovered that the underground river has a second floor, which means that there are small waterfalls inside the cave. They also found a cave dome measuring 300 m (980 ft) above the underground river, rock formations, large bats, a deep water hole in the river, more river channels, and another deep cave, as well as marine creatures and more. Deeper areas of the underground river are almost impossible to explore due to oxygen deprivation.[clarification needed]