The plain is more than 1,000 km long from south to north and 300 to 400 km wide from east to west, covering an area of 350,000 km ² . At its two ends lie the Changbai Mountains in the east and the Greater Khingan Mountains in the west. To its north are the Lesser Khingan Mountains, and to its south, it is bounded by the Liaodong Bay. The Northeast China Plain comprises three separate minor plains, namely, the Liaohe Plain, the Songnen Plain and the Sanjiang Plain, with the Songnen Plain being the biggest of the three and making up the main part of the Northeast China Plain.

A glimpse of the Northeast China Plain

Geologically, the Northeast China Plain has two saddles, with the line between Kaiyuan, Liaoning Province and Huinan, Jilin Province as the boundary (43°N): To the north, a saddle relates to the Jilin–Heilongjiang fold system, and to the south the lower Liaohe saddle relates to the Sino-Korean para-platform. On the fringes of the Northeast China Plain are a diluvial plain and platform with an elevation of about 200 m. The shape of the platform is apparent in the north, but takes on a look of eroded low hilly land in the south. In the southwestern part of the Northeast China Plain, an Aeolian landform has evolved, so that the land in this region is largely covered by sand dunes. As the Northeast China Plain lies in the temperate and warm temperate zones, it has a continental monsoon climate, where the summer is warm, short, and rainy; the winter is long and cold with little snowfalls, and seasonal winds alternate between the summer and winter. The Liaohe River and the Songhua River systems run through the plain, respectively in the south and in the north, with the Songliao Watershed as the division of the two river systems. To the north of the Northeast China Plain is the Songnen Plain, evolved by alluvial deposits carried down from the Songhua and Nenjiang rivers, and to the south is the Liaohe Plain, formed as a result of accumulated alluvial sediments from the Liaohe River. To the east of the Lesser Khingan Mountains and north of the Changbai Mountains lies the Sanjiang Plain, located where the Heilong, Songhua, and Wusuli rivers converge.

Wetlands and marshlands that have fertile soil and rich resources are widely scattered across the Northeast China Plain. The plain is an important animal husbandry base and a major producer of grain crops and soybeans. The plain is also known for the development of steel, machinery, energy, and chemical industries.