Guangzhou is the capital and the sub-provincial city of Guangdong Province in the southern part of the People's Republic of China. The city is also known by an older English-language name, Canton. It is a port on the Pearl River, navigable to the South China Sea, and is located about 120 km (75 miles) northwest of Hong Kong. As of the 2000 census, the city has a population of 6 million, and a metropolitan population of roughly 8.5 million (though some estimates are as high as 12.6 million)making it the most populous city in the province and the third most populous metropolitan area in mainland China. The official estimate of the city's population at end 2006 by the Provincial Government was 9,754,600.