 Established by an Act of the U.S. Congress on March 3, 1863, the Niobrara Reservation was officially recognized in an Executive Order dated February 27, 1866, and in treaties dated November 16, 1867 and April 29, 1868.Additional executive orders applying to the reservation were dated August 31, 1869, December 31, 1873, and February 9, 1885.In those initial years, tribal members selected as homesteads and as allotments; were designated for use as an Indian agency, school, and mission.