river in the Balkans, rising in Kosovo in the Mokra Planina (mountains) and flowing eastward to Kosovska Mitrovica, then northward to join the Zapadna Morava River in Serbia. Its length is 171 miles (276 km), and it has a drainage area of 3,100 sq miles (8,000 sq km). Major tributaries are the Raška, Studenica, and Sitnica. The adjacent upland is forested, but there are croplands in the stream valleys, where the settlement pattern is frequently one of tightly grouped hamlets.