The area includes land lying on the North American Plate and Siberian land east of the Chersky Range. Historically, it formed a land bridge that was up to 1,000 kilometres (620 miles) wide at its greatest extent and which covered an area as large as British Columbia and Alberta together, totaling approximately 1,600,000 square kilometres (620,000 square miles). Today, the only land that is visible from the central part of the Bering land bridge are the Diomede Islands, the Pribilof Islands of St. Paul and St. George, St. Lawrence Island, and King Island.
The term Beringia was coined by the Swedish botanist Eric Hultén in 1937. During the ice ages, Beringia, like most of Siberia and all of North and Northeast China, was not glaciated because snowfall was very light. It was a grassland steppe, including the land bridge, that stretched for hundreds of kilometres into the continents on either side.
It is believed that a small human population of at most a few thousand arrived in Beringia from eastern Siberia during the Last Glacial Maximum before expanding into the settlement of the Americas sometime after 16,500 years BP. This would have occurred as the American glaciers blocking the way southward melted, but before the bridge was covered by the sea about 11,000 years BP.
Before European colonization, Beringia was inhabited by the Yupik peoples on both sides of the straits. This culture remains in the region today along with others. In 2012, the governments of Russia and the United States announced a plan to formally establish "a transboundary area of shared Beringian heritage". Among other things this agreement would establish close ties between the Bering Land Bridge National Preserve and the Cape Krusenstern National Monument in the United States and Beringia National Park in Russia.
The remains of Late Pleistocene mammals that had been discovered on the Aleutians and islands in the Bering Sea at the close of the nineteenth century indicated that a past land connection might lie beneath the shallow waters between Alaska and Chukotka. The underlying mechanism was first thought to be tectonics, but by 1930 changes in the icemass balance, leading to global sea-level fluctuations, was viewed as the cause of the Bering Land Bridge. In 1937, Eric Hultén proposed that around the Aleutians and the Bering Strait region were tundra plants that had originally dispersed from a now-submerged plain between Alaska and Chukotka, which he named Beringia after Vitus Bering who had sailed into the strait in 1728. The American arctic geologist David Hopkins redefined Beringia to include portions of Alaska and Northeast Asia. Beringia was later regarded as extending from the Verkhoyansk Mountains in the west to the Mackenzie River in the east. The distribution of plants in the genera Erythranthe and Pinus are good examples of this as genera members are found in Asia and the Americas with a high degree of similarity.