Chinese:: Mandarin form of the surname 江 meaning ‘river’ in Chinese: (i) from Jiang (江) the name of an ancient state (located in present-day Zhengyang in Henan province) in the Shang dynasty (1600–1046 BC) and Western Zhou dynasty (1046–771 BC). After it was annexed by the state of Chu in 623 BC the name of the state was adopted as a surname. (ii) from the name of Jiang Chugong (江處恭). In the earlier Northern Song Dynasty (960–1127 AD) in Quanzhou in Fujian province Weng Qiandu had six sons and gave different surnames to each of them. His second son Weng Chugong was given the surname Jiang. Thus he was also called Jiang Chugong. He and his brothers all became celebrated officials known as “the Six Laureates”. Mandarin form of the surname 蔣: from Jiang (蔣) the name of an ancient state (probably located in present-day Henan province) which was granted to Bo Ling a grandson of King Wen of Zhou(1152–1056 BC). After this state was annexed by the state of Chu people kept the name of the state as their surname. Mandarin form of the surname 姜 meaning ‘ginger’ in Chinese: the surname is traced back to the legendary Yan Di or the ‘Yan Emperor'. He was born near Jiang Shui (姜水 literally meaning 'River Jiang ') a river in present-day Shaanxi province. He and his descendants acquired 姜 (Jiang) part of the placename as their surname. A famous descendant Jiang Shang known as Jiang Ziya or Jiang Tai Gong (c. 11th century BC) an official during the Western Zhou dynasty (1046–771 BC) was granted the state of Qi which is located mainly in present-day Shandong province.
Source: Dictionary of American Family Names 2nd edition, 2022