linguistic:paraphrasing
Political status

Under the United Nations Convention on the Law of the Sea treaty (UNCLOS), artificial islands are not considered harbor works (Article 11) and are under the jurisdiction of the nearest coastal state if within 200 nautical miles (370 km) (Article 56). Artificial islands are also not considered islands for purposes of having their own territorial waters or exclusive economic zones, and only the coastal state may authorize their construction (Article 60); however, on the high seas beyond national jurisdiction, any "state" may construct artificial islands (Article 87).

The unrecognised micronation known as the Principality of Sealand (often shorted to simply "Sealand") is entirely on a single artificial island.