 On March 23, 1889, President Benjamin Harrison signed legislation which opened up the two million acres (8,000 km²) of the Unassigned Lands for settlement on April 22, 1889.It was to be the first of many land runs, but later land openings were conducted by means of a lottery because of widespread cheating—some of the settlers were called Sooners because they had already staked their land claims before the land was officially opened for settlement.Indian Territory (lands owned by the Five Civilized Tribes and other Indian tribes from east of the Mississippi River) and Oklahoma Territory (lands set aside to relocate Plains Indians and other Midwestern tribes, as well as the recently settled "Unassigned Lands" and the Neutral Strip) were formally constituted by Congress on May 2, 1890 in the Oklahoma Organic Act.