Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast China (simplified Chinese: 东北; traditional Chinese: 東北; pinyin: Dōngběi). This region is the traditional homeland of the Xianbei, Korean, Khitan, and Jurchen peoples, who built several dynasties in northern China. The region is also the home of the Manchus, after whom Manchuria is named.

Manchuria can refer to any one of several regions of various size. These are, from smallest to largest:

"Manchuria" is a translation of the Manchu word Manju (Chinese language: Mǎnzhōu). According to the Manchu Veritable Records, the name Manju was originally given by the legendary dynastic founder Bukūri Yongšon to the country he established when he united the three warring clans of Odoli, at the location of the modern city of Dunhua in Jilin province. This name was used in Chinese documents until the early 20th century, when Manchuria was converted into three provinces by the late Qing government. Since then, the "Three Eastern Provinces" (東三省) was officially used by the Qing government in China to refer to this region, and the post of Viceroy of Three Northeast Provinces (東三省總督) was established to take charge of these provinces. After the 1911 revolution, which resulted in the collapse of the Manchu-established Qing Dynasty, the name of the region where the Manchus originated was known as the Northeast in official documents in the newly founded Republic of China, in addition to the "Three Northeast Provinces".