The 180th meridian or antimeridian is the meridian 180° both east and west of the prime meridian in a geographical coordinate system. The longitude at this line can be given as either east or west.

Wrangel Island is an island of the Chukotka Autonomous Okrug, Russia. It is the 92nd largest island in the world and roughly the size of Crete. Located in the Arctic Ocean between the Chukchi Sea and East Siberian Sea, the island lies astride the 180th meridian. The International Date Line is therefore displaced eastwards at this latitude to keep the island, as well as the Chukchi Peninsula on the Russian mainland, on the same day as the rest of Russia. The closest land to Wrangel Island is the tiny and rocky Herald Island located 60 kilometres to the east. Its straddling the 180th meridian makes its north shore at that point both the northeasternmost and northwesternmost point of land in the world by strict longitude; using the International Date Line instead those respective points become Herald Island and Alaska's Cape Lisburne.