The only exceptions to Bangladesh's low elevations are the Chittagong Hills in the southeast, the Low Hills of Sylhet in the northeast, and highlands in the north and northwest. The Chittagong Hills constitute the only significant hill system in the country and, in effect, are the western fringe of the north-south mountain ranges of Burma and eastern India. The Chittagong Hills rise steeply to narrow ridge lines, generally no wider than , with altitudes from above sea level. At altitude, the highest elevation in Bangladesh is found at Saka Haphong, in the southeastern part of the hills. Fertile valleys lie between the hill lines, which generally run north-south. West of the Chittagong Hills is a broad plain, cut by rivers draining into the Bay of Bengal, that rises to a final chain of low coastal hills, mostly below , that attain a maximum elevation of . West of these hills is a narrow, wet coastal plain located between the cities of Chittagong in the north and Cox's Bazar in the south.