NEN RIVER

Wade-Giles romanization Nen Chiang, Pinyin Nen Jiang, also called Nonni River river in northeastern China. The Nen River is the principal tributary of the Sungari River, which is itself a tributary of the Amur River. The Nen River proper rises in the area where the Greater and Lesser Khingan ranges come together in northern Heilungkiang province and Inner Mongolia. It then flows southward, forming part of the border between these two areas as it crosses the northern section of the Manchurian Plain to join the Sungari just east of Ta-an in Kirin province. It receives the waters of a great many tributaries that run off the eastern slopes of the Greater Khingan and the western slopes of the Lesser Khingan ranges. Although annually frozen for some four months in winter and subject to serious flooding during the summer months, especially around its confluence with the Sungari, the Nen River is an important water route, navigable by small steamers as far as Tsitsihar (Ch'i-ch'i-ha-erh) and by small craft much farther to the north. The river was even more important in the early period of Chinese settlement in Heilungkiang in the 19th century, when rivers were virtually the only means of communication. In the wide, flat Manchurian Plain, the gradient of the Nen River is very low and the river's course meanders. The plain is subject to flooding during the spring thaw and again during the summer. The plain itself is wet and in places waterlogged, having many salt bogs, swamps, and brackish lakes. The total length of the Nen River is 725 miles (1,170 km).