western mountains, respectively. The territories of the different tribes were defined by multiple and varied treaties with the United States, generally shrinking their land boundaries with each revision. The Ojibwe and Cree people today jointly share the Rocky Boy's Reservation in north-central Montana. Rocky Boy's reservation was created after most of the others as a home for some of the "landless" tribes who did not obtain reservation lands elsewhere. The creation of the reservation was largely due to the efforts of the Chippewa leader Stone Child (aka "Rocky Boy"). The Little Shell Chippewa also have a presence in Montana, however they do not have a reservation. Other native people had a significant presence in Montana, though today do not have a reservation within the state. These nations included the Lakota, the Arapaho, and the Shoshone. The Kiowa and the Kiowa-Apache claim an early history in the late 17th century) as nomadic hunters between the Yellowstone and Missouri. Louisiana Purchase On April 30, 1803, the Louisiana Purchase Treaty was signed by representatives of the U.S. at Paris, France. The United States Senate ratified the treaty on October 20 and President Thomas Jefferson announced the treaty to the American people on July 4, 1803. The area covered by the purchase included much of the present-day United States between the Continental Divide and the Mississippi River, encompassing the Great Plains including part of what is now Montana, particularly the Missouri River drainage. The rights to the Louisiana Purchase territory cost the U.S. $15 million, which came out to an average of 3 cents an acre. On March 10, 1804, a formal ceremony was conducted in St. Louis, Missouri, to transfer ownership of the territory from France to the United States of America. The lands of present-day Montana were practically unknown and too distant from the seats of power for this political boundary change to have much impact upon them, but the Louisiana Purchase would prove a sea-change for the area. Lewis and Clark Expedition The Louisiana Purchase sparked interest in knowing the character of the lands the nation had purchased, including their flora and fauna and the peoples who inhabited them. President Thomas Jefferson, an advocate of exploration and scientific inquiry, had the Congress appropriate $2,500 for an expedition up the Missouri River and down the Columbia River to the Pacific Ocean. He had envisioned an expedition of this nature since at least