Pearl River Delta Region (珠江三角洲)
After the Yangzi River (Changjiang [長江]) in central China and the Yellow River (Huanghe [黃河]) in northern China, the Pearl River (Zhujiang [珠江]) in southern China is the third longest river.
The name Pearl River is a bit of a misnomer as it is only a very short portion around Guangzhou (廣州) that is actually called the Pearl River. There are three rivers, the North River (Beijiang [北江]), the East River (Dongjiang [東江]) and the West River (Xijiang [西江]) which forms a vast river system and merges around Guangzhou before discharging into the South China Sea (Nanhai [南海]) as an extensive delta region. The rich soil and in combination with a sub-tropical climate makes it the bread basket of China. Hence, Guangdong Province (廣東省) is by far the richest province today. This region is centered around the three major cities of Guangzhou, Hong Kong (Xianggang [香港]) and Macau (Aomen [澳門]) to form the Pearl River Delta Region (Zhujiangsanjiaozhou [珠江三角洲]).
Shown below is a map of the region:
Within this region are some of the better known areas from where people in the past have ventured beyond the seas to make a living and for some to make fortunes:
Siyi (四邑) consisting of Xinhui (新會), Taishan (台山), Kaiping (開平) and Enping (恩平)
Sanyi (三邑) consisting of Panyu (番禺), Nanhai (南海) and Shunde (順德)
People also came from another two areas not in the Pearl River Delta Region but in northeastern Guangdong Province:
The majority of them were Cantonese speaking but those from Chaozhou (潮州) speak their own dialect which is akin to the Fujian Minnan dialect (福建閔南話) and they mostly migrated to Thailand. Within the Zhongshan (中山) area there were those from the Longdu (隆都) area just southwest of Zhongshan City (中山市) who also speak a dialect akin to Chaozhou. Another group of people were the Hakka/Kejia (客家) who ventured far and wide from South East Asia to the Pacific Islands, Central America and the Caribbean.
Southern Fujian Province (福建省), around the Xiamen (Amoy is the Minnan pronunciation) (廈門) area was also the departure point for people migrating overseas, especially to South East Asia and further afield, like Australia. They speak a different dialect called Hokkien (福建話) or Minnan (閩南話). Shown below is a satellite map of this region with the departure port of Xiamen (lower right hand side).