In acquiring, preparing, and distributing public land to private ownership, the federal government generally followed the system set forth by the Land Ordinance of 1785. Federal exploration and scientific teams would undertake reconnaissance of the land and determine Native American habitation. Through treaties, the land titles would be ceded by the resident tribes. Then surveyors would create detailed maps marking the land into squares of six miles (10 km) on each side, subdivided first into one square mile blocks, then into lots. Townships would be formed from the lots and sold at public auction. Unsold land could be purchased from the land office at a minimum price of $1.25 per acre.