2. The three northeastern provinces, also known as the "three northeastern provinces", are the three administrative regions of Northeast China after the late Qing Dynasty. They have nothing to do with the geographical and cultural northeast, but the collective name of the three provincial administrative units in the northeast has changed in different periods. In contemporary China, the three northeastern provinces are Liaoning, Jilin and Heilongjiang. For a long time, its scope is not equal to the northeast.

3. Liaoning, referred to as "Liao" for short, is the provincial administrative region of People's Republic of China (PRC) (China), with Shenyang as its capital. The total area of Shenyang is 12948 square kilometers, and the urban area is 3495 square kilometers.

Jilin, referred to as "Ji" for short, is the provincial administrative region of People's Republic of China (PRC) (China), with Changchun as its capital. Changchun has a total area of 20565 square kilometers. Among them, the urban area is 7557 square kilometers, and the central built-up area is 506.33 square kilometers.

5. Heilongjiang Province, referred to as Heilongjiang Province for short, is a provincial administrative region of People's Republic of China (PRC), with Harbin as its capital. Harbin has a total area of 53 1000 square kilometers, of which the urban area is 7086 square kilometers.