Hong Kong is 3 times larger than Philadelphia.
Area: 1,104 km2 World Factbook
Population: 7,112,688 (July 2014) World Factbook
Hong Kong, alternatively known by its initials H.K., is a former British Colony and is currently a Special Administrative Region of the People's Republic of China, enclosed by the Pearl River Delta and South China Sea. Wikipedia
Area: 370 km2 calculated
Philadelphia is the largest city in the Commonwealth of Pennsylvania, the fifth-most-populous city in the United States, and the core of the sixth-largest metropolitan area in the country. Wikipedia