(sûr'mə, sʊr'mä) , river, 320 mi (515 km) long, rising in the Manipur hills, NE India, and flowing generally W through the Surma valley, where the river is dispersed into numerous streams; rejoined at the western end of the valley, the Surma joins the Meghna River in NE Bangladesh. The alluvial valley, astride the India-Bangladesh border, is fertile; rice, tea, and oilseed are the chief crops.