Congress approves legislation guaranteeing pre-emption for Minnesota settler-colonists squatting on lands that have not been surveyed. Technically, the land could be sold only after being surveyed, but whites had poured into lands purchased from the Dakota and Ojibwe, sometimes making substantial improvements before the surveyors completed their work. This act, sponsored by delegate Henry H. Sibley, allows the settler-colonists to purchase their land after the fact of settlement.