The Pegu Yoma range separates it from Toungoo district, and forms the water-parting between the rivers Irrawaddy and Sittang; there are also many small elevations.
Of the rivers of Burma the Irrawaddy is the most important.
The principal river of the district is the Irrawaddy, which debouches on the sea at its eastern extremity through a delta intersected with salt water creeks, among which the Pyamalaw, Pyinzalu, Kyunton, and Ngawun Shagegyi or Bassein river rank as important arms of the sea.
Woodthorpe was followed into Burmese fields by many others; and amongst the earliest travellers to those mysterious mountains which hide the sources of the Irrawaddy, the Salween and the Mekong, was Prince Henri d'Orleans Burma was rapidly brought under survey; Siam was already in the 'mapmaking hands of James M'Carthy, whilst Curzon and Warrington Smyth added much to our knowledge of its picturesque coast districts.
The comparatively restricted area which still remains for close investigation includes the most easterly sources of the Brahmaputra, the most northerly sources of the Irrawaddy, and some 300 m.
