The Hopewell complex developed out of Adena and other late Eastern groups. It had two main foci, in the Ohio valley and Illinois, where mound-building was most intensive and exotic materials most common, but its cultural connections embrace a much wider area in which trade both in raw materials and finished goods was highly developed. This is known as the 'Hopewell interaction sphere'.
Building on the foundations of the intercommunity exchange networks that had operated for thousands of years, this trade was now much more organized, probably by community leaders.
Certain Hopewell centres now specialized in making goods from exotic raw materials and trading them on: these included ear spools of Great Lakes copper and platform pipes of Ohio pipestone. Small pottery jars and other objects decorated with bird motifs appear in burials over a wide area. It has been suggested that such similarities reflect some shared ritual beliefs.
Ceremony and ritual can also be seen in the great elaboration of burial practices in the Hopewell period. After about AD 400 both mound-building and the substantial interregional trade ceased, for reasons unknown.
