Tombaugh Regio

Tombaugh Regio is the third-largest and most populated Regio of Pluto, with 11.9 million people. The Regio is composed by the Sputnik Sea and the landmasses of West Pandemonium Dorsa, Al-Idrisi, Baret, Tenzing, Hillary and Zheng He montes, the Cousteau Rupes and numerous colles, the principals being: Soyuz, Coleta De Dados, Columbia, Challenger & Astrid.

Bodies of Water
The Mare Sputnik is Pluto's second-largest body of water. Covering the Sputnik Planitia, it lies on the centre of the planet. It has a salinity of approximately 29 grams per litre.

It is bounded by the Central Islands Ring to the west, the Tartarus Dorsa to the east, the West Pandemonium Dorsa to the south and the Hayabusa, Pioneer and Voyager Terrae to the north.