Located on China's southern coast and nearest to the Hong Kong Special Administrative Region, Guangdong Province is the economic focal point of the area officially referred to as "South China". Guangdong Province covers 68,700 square miles and has a population of approximately 72 million. First to develop since China's opening to the outside world, Guangdong currently leads the nation in industrial development. This region continues to enjoy high annual growth rates from its proximity to its economically advanced sponsor, Hong Kong. The Pearl River Delta is the zenith of industrial progress in Guangdong. This region includes the cities of Guangzhou, Foshan, Huizhou, Jiangmen, Zhongshan, Dongguan, and the Special Economic Zones (SEZs) of Shenzhen and Zhuhai. The SEZs have strict entry restrictions and special commercial and political privileges to foster rapid development. Guangdong also has the most advanced infrastructure and educated labor force in all of China.