The Siyi dialect is mainly distributed along the
drainage basin of the Tan river (), as well as part of the region west of the main stream of the
Xi River, near to the confluence of the two rivers. Most of the region in which Siyi is spoken is administered by the prefecture-level city of Jiangmen, including the
Jiangmen city districts of
Jianghai,
Pengjiang and Xinhui, as well as the
county-level cities of
Taishan,
Kaiping,
Enping and the southeastern part of
Heshan, but the dialect is also spoken in parts of
Zhuhai, the town of Guzhen in
Zhongshan and the town of Jun'an in
Foshan. In terms of geographic extremes, Siyi is spoken furthest north in Yayao (雅瑶), Heshan; furthest south in
Xiachuan Island, Taishan; furthest east in Hongqi (红旗), Zhuhai; and furthest west in Naji (那吉), Enping. The total geographic area of the region is approximately 9000 square kilometers and the total number of speakers is estimated at 3.9 million in 2010. == Dialectal variation ==