on february 18, 1861, six chiefs of the southern cheyenne and four of the arapaho signed the treaty of fort wise with the united states. this was at bent's new fort at big timbers. this was near what is now lamar, colorado. lamar had been recently leased by the u.s. government, and the name changed to fort wise. the native americans gave most of the lands given to them by the fort laramie treaty to the united states.