The classification of the Indigenous peoples of the Americas is based upon cultural regions, geography, and linguistics. Anthropologists have named various cultural regions, with fluid boundaries, that are generally agreed upon with some variation. These cultural regions are broadly based upon the locations of the Indigenous peoples of the Americas from early European and African contact beginning in the late 15th century. When Indigenous peoples have been forcibly removed by nation-states, they retain their original geographic classification. Some groups span multiple cultural regions.