The rectangular survey system was enacted by the Land Ordinance Act of 1785. Now known as the Public Land Survey System (PLSS), this system divided what is now Cass County into townships, sections and smaller tracts called Quarter-Quarters and Government Lots. This surveyed land was sold by the government in order to generate revenue. The land corners placed by the PLSS survey in Cass County provided the foundation for all transactions involving land that followed. The original PLSS survey in what is now Cass County took place from 1857 to 1875 and there were approximately 7,800 original corners established. Later surveys by the Federal government between 1915 and 1933 defined Reservation allotments and added about 3000 corners.