Hong Kong is not an island—it's a Special Administrative Region (SAR) comprising Hong Kong Island, Kowloon Peninsula, New Territories, and 260+ outlying islands.
It reverted from British colonial rule to the People's Republic of China on 1 July 1997, under the "One Country, Two Systems" principle, guaranteeing its capitalist system, legal framework, and high-degree autonomy for 50 years (until 2047).