Edges where Earth's plates meet.

Limits formed by nature itself.

Guardian enforcing limits and borders.

a framework to describe limits to the impacts of human activities on the Earth system.

Personal boundaries or the act of setting boundaries is a life skill that has been popularized by self help authors and support groups since the mid-1980s.

an independent regulatory agency that was founded in the year 2011 through the making of the Constitution of Kenya.

The Boundaries of Hong Kong, officially the Boundary of the Administrative Division of the Hong Kong Special Administrative Region of the People's Republic of Chinabasiclaw.gov.hk - Description of the Boundary of the Administrative Division of the Hong Kong Special Administrative Region of the People’s Republic of Chinaelegislation.gov.hk - 中華人民共和國香港特別行政區行政區域界綫文字表述 Description of the Boundary of the Administrative Division of the Hong Kong Special Administrative Region of the People’s Republic of China, is a regulated administrative border with border control in force under the One country, two systems constitutional principle, which separates the Hong Kong Special Administrative Region from mainland China, by land border fence of and maritime boundary of , enforcing a separate immigration and customs-controlled jurisdiction from mainland China.