The White House,
- August 18, 1908.
That order was preceded by an order of President U.S. Grant of Sept. 12, 1872, which created the 1.8 million acre Malheur Indian Reservation (I've been unable to find a copy of that EO on the 'net). According to Wikipedia, that order was "discontinued" in 1879:
The Malheur Indian Reservation was an Indian reservation established for the Northern Paiute in eastern Oregon and northern Nevada from 1872 to 1879. The federal government "discontinued" the reservation after the Bannock War of 1878, under pressure from European-American settlers who wanted the land, a negative recommendation against continuing it by its agent William V. Rinehart, the internment of more than 500 Paiute on the Yakama Indian Reservation, and reluctance of the Bannock and Paiute to return to the lands after the war.
Currently, according to the USFWS, the refuge contains 187,757 acres, and underwent significant expansions in 1935 and 1942:
The 65,000 acre Blitzen Valley was purchased in 1935 and added to the refuge to secure water rights for Malheur and Mud Lake. With the creation of the Civilian Conservation Corps (CCC) in 1933, the refuge was able to use this additional manpower in 1935 to begin major improvements on the refuge. The CCC constructed most of the infrastructure in the Blitzen Valley including the Center Patrol Road which travels through the center of the refuge. The 14,000 acre Double-O unit was added to the refuge in 1942 and provides important shorebird habitat, as well as waterfowl nesting areas.
That's all I have for now. Would welcome any additions or clarifications.