The Pearl River Delta Metropolitan Region is the low-lying area surrounding the Pearl River estuary, where the Pearl River flows into the South China Sea. It is one of the most densely urbanized regions in the world, and is often considered a megacity. It is now the wealthiest region in South China and one of the wealthiest in the whole of China along with the Yangtze River Delta in East China and Jingjinji in North China. The region's economy is referred to as Pearl River Delta Economic Zone. It is also part of the Guangdong-Hong Kong-Macau Greater Bay Area.
The PRD is a megalopolis, with future development into a single mega metropolitan area, yet itself is at the southern end of a larger megalopolis running along the southern coast of China, which include metropolises such as Chaoshan, Zhangzhou-Xiamen, Quanzhou-Putian and Fuzhou. The nine largest cities of the PRD had a combined population of 57.15 million at the end of 2013, comprising 53.69% of the provincial population. According to the World Bank Group, the PRD has become the largest urban area in the world in both size and population.