The completion of the Hong Kong-Zhuhai-Macau Bridge marks not only a record-setting achievement in engineering, but also a materialisation of ongoing efforts by the People's Republic of China to engage in cooperative projects aimed at expanding and deepening integrative connections with the semi-autonomous Special Administrative Regions of Macau and Hong Kong. This paper explores the colonial and post-colonial social construction of Hong Kong as a political-economic island, and the implications this carries into the tensions and open conflicts that have unfolded under the One Country, Two Systems agreement. Using the bridge as a case, it critically examines the geopolitical and biopolitical dimensions of infrastructure as a practice of subnational (de)bordering. The case renders visible a contemporary moment where infrastructure occupies a central position at the conjuncture of technology, advanced governmentality and shifting geographies of sovereignty in the People's Republic of China, within subnational city-regional development plans, as well as internationally in projects, such as the geographically expansive Belt and Road Initiative. A close examination of the Bridge project highlights the constructed and contested nature of borders, as well as the complex identities and ideologies that define them. [ABSTRACT FROM AUTHOR]