The first known inhabitants in Arkansas were the Native Americans. The first archaeological evidence of human habitation in Arkansas dates back to the Paleo-Indian period, which began around 10,000 BC. The Paleo-Indians were nomadic hunters and gatherers who lived in small, scattered bands. They were followed by the Archaic Indians, who lived in Arkansas from about 8000 BC to 1000 BC. The Archaic Indians were also nomadic, but they began to develop more permanent settlements and to practice agriculture. The Woodland Indians, who lived in Arkansas from about 1000 BC to 1000 AD, were the first Native Americans to build large, permanent settlements. They also developed a complex social structure and a rich cultural tradition. The Mississippian Indians, who lived in Arkansas from about 1000 AD to 1500 AD, were the last major Native American group to inhabit the state. They built large ceremonial centers, such as the one at Spiro Mounds, and developed a complex political and economic system.