Bangladesh is a tropical country, situated mainly on the deltas of large rivers flowing from the Himalayas. The Brahmaputra River, known locally as the Jamuna, unites with part of the Ganges to form the Padma, which, after its juncture with a third large river, the Meghna, flows into the Bay of Bengal. Offshoots of the Ganges-Padma, including the Burishwar, Garai, Kobadak, and Madhumati, also flow south to the Bay of Bengal. No part of the delta area is more than 150 m (500 ft) above sea level, and most of it is but a meter or two (a few feet) above sea level. Its soil consists mostly of fertile alluvium, which is intensively farmed; mineral deposits are negligible. During the rainy season floodwater covers most of the land surface, damaging crops and injuring the economy. The northwestern section of the country, drained by the Tista (Teesta) River, is somewhat higher and less flat, but the only really hilly regions are in the east, notably in the Chittagong Hill Tracts to the southeast and the Sylhet District to the northeast. Near the Myanmar border, in the extreme southeast, is the Keokradong, which at 1,230 m (4,034 ft) is the highest peak in Bangladesh.