|Region||Sichuan, Chongqing, Hubei and Shaanxi|
|About 90 million (date missing)|
Chengdu-Chongqing is the largest deep-green area.
Chengdu-Chongqing dialect or Cheng–Yu (Chinese: 成渝; pinyin: Chéng-Yú; Sichuanese Pinyin: Cen2yu2, local pronunciation: [tsʰən˨˩y˨˩]) is the most widely used branch of Southwestern Mandarin, with about 90 million speakers. It is named after Chengdu, the capital city of Sichuan, and Chongqing, which was split from Sichuan in 1997. It is spoken mainly in northern and eastern Sichuan, the northeastern part of the Chengdu Plain, several cities or counties in southwestern Sichuan (Panzhihua, Dechang, Yanyuan, Huili and Ningnan), southern Shaanxi and western Hubei.
This uniform dialect is formed after the great migration movement in Ming and Qing dynasty, and is greatly influenced by the Chinese varieties the immgrants spoke Mandarin from Hubei, Xiang and Gan. So it keeps fewer characteristics of Sichuan's original Ba-Shu Chinese than other Sichuanese dialects, such as Minjiang dialect.