Terms such as Northeast Asia, North East Asia, or Northeastern Asia refer to a subregion of Asia: the northeastern landmass and islands, bordering the Pacific Ocean. It includes, paradoxically, the core countries of East Asia (see map).
The term Northeast Asia was popularized during the 1930s by the American historian and political scientist Robert Kerner. Under Kerner's definition, "Northeast Asia" included the Mongolian Plateau, the Manchurian Plain, the Korean Peninsula, and the mountainous regions of the Russian Far East, stretching from Lena River in the west to the Pacific Ocean in the east.