Cahokia (tribe) in the context of "Illinois Confederation"

The Illinois Confederation, also referred to as the Illiniwek or Illini, were made up of a loosely organized group of 12 or 13 tribes who lived in the Mississippi River Valley. Eventually, member tribes occupied an area reaching from Lake Michigan to Iowa, Illinois, Missouri, and Arkansas. The five main tribes were the Cahokia, Kaskaskia, Michigamea, Peoria, and Tamaroa. Other related tribes are described as the Maroa (which may have been the same as Tamaroa), Tapourao, Coiracoentanon, Espeminka, Moingwena, Chinkoa, and Chepoussa. By 1700, only the Cahokia, Kaskaskia, Michigamea, Peoria, and Tamaroa remained. Over time, these tribes continued to merge, with the Tamaroa joining the Kaskaskia, the Cahokia joining the Peoria, and with a portion of the Michigamea merging with the Kaskaskia and the remainder merging with the Quapaw.

The spelling "Illinois" was derived from the transliteration by French explorers of iliniwe to the orthography of their own language. The tribes are estimated to have had tens of thousands of members, before the advancement of European contact in the 17th century that inhibited their growth and resulted in a marked decline in population.