When the United States annexed Montana land, it imposed federal laws on the newly acquired property and the people already on those lands. Despite tens of thousands of years that native peoples already lived in Montana—the U.S. government dictated Indian policy. Treaties, executive orders, and congressional legislation created that policy. American Indians fought this alien system in the ‘Indian Wars’ of the nineteenth century. Federal Indian policy alternately attempted to isolate Indians on reservations and to assimilate Indians into the Euro-American population.