LandThe Chittagong Hills in eastern and southeastern Bangladesh include the highest and most rugged parts of the nation, with elevations rising to more than 1,200 m (4,000 ft) above sea level. The remainder of Bangladesh is generally low-lying, with elevations approaching only 300 m (900 ft) in the hills of the northwest and northeast and considerably lower on the vast deltaic plains on the BRAHMAPUTRA, GANGES, and Meghna rivers. The lowlands of the delta region are crisscrossed by numerous distributaries of the main rivers.

About 6% of the total land area of Bangladesh is permanently under water, and two-thirds is flooded for part of the year. The floods often result in great loss of life, crops, and property damage but are, nonetheless, of special value to agricultural Bangladesh for the sediments (alluvium) that the muddy floodwaters deposit on the land. These alluvial soils are rich minerals and other nutrients needed for plant growth.