What is the largest cave chamber in the world (by area)?

The largest cave chamber in the world by area is Sarawak Chamber. It lies inside Gua Nasib Bagus, or Good Luck Cave, in Gunung Mulu National Park in Malaysian Borneo.

British cavers discovered the chamber during the 1981 Mulu'80 expedition. It was named after Sarawak, the Malaysian state where the national park is located. The chamber measures about 600 metres long, 435 metres wide and up to 115 metres high.

Laser scanning in 2011 estimated its floor area at roughly 164,459 square metres and its volume at about 9.58 million cubic metres. Those measurements make it the world's largest known cave chamber by area, although it is not the largest by every possible measurement.

That distinction causes common mix-ups. China's Miao Room is larger by volume, while Carlsbad Caverns' Big Room was once considered the world's largest underground chamber. Deer Cave is another enormous Mulu feature, but it is a passage rather than the world's largest chamber by area.