 This era was a period of economic transition . The dominant enterprise in the area since the 17th century had been the fur trade . The Dakota Sioux , and later the Ojibwe , tribes hunted and gathered pelts trading with French , British , and later American traders at Grand Portage , Mendota , and other sites . This trade gradually declined during the early 19th century as demand for furs in Europe diminished . The lumber industry grew rapidly , replacing furs as the key economic resource . Grain production began to develop late during this time as an emerging economic basis as well . Saw mills , and later grain mills , around Fort Snelling and Saint Anthony Falls in east @-@ central Minnesota became magnets for development . By the end of the era east @-@ central Minnesota had replaced northern Minnesota as the economic center of the area . 
