Wrangel Island (Russian: О́стров Вра́нгеля, tr. Ostrov Vrangelya, IPA: [ˈostrəf ˈvrangʲɪlʲə]; Chukot: Умӄиԓир, romanized: Umqiḷir) is an island of the Chukotka Autonomous Okrug, Russia. It is the 91st 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 avoid the island as well as the Chukchi Peninsula on the Russian mainland, to keep the island 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 (32 nautical miles) to the east. Wrangel Island is the last known place where woolly mammoths survived, until around 4,000 years ago.

Most of Wrangel Island and the nearby Herald Island is a federally protected nature sanctuary administered by Russia's Ministry of Natural Resources and Environment. The island, and its surrounding waters, were classified as a "Zapovednik" (a "strict nature reserve") in 1976 and, as such, receive the highest level of protection and exclude practically all human activity other than for scientific purposes. The Chukotka Regional government extended the marine protected area out to 24 nmi (44 km) in 1999. As of 2003, there were four rangers who reside on the island year-round, while a core group of about 12 scientists conduct research during the summer months.