Protection As originally established in 1910, Big Hole Battlefield National Monument consisted of just five acres where the siege had taken place. Enlarged to 200 acres in 1939, the national monument then included all of the Siege Area plus the route of Colonel Gibbon's approach and the area along the foot of Battle Mountain from which he had launched his initial attack. Still outside the boundary of the national monument, however, was the Nez Perce Encampment Area where some of the fiercest fighting had occurred on the morning of August 9. Further additions, authorized by an act of Congress in 1963 and accomplished over the next decade, brought the Encampment Area and the development site into the unit. Bloody Gulch, where most of the Nez Perce withdrew while the warriors held their attackers at bay, remains outside on private land. Since its establishment as a national monument in 1910, Big Hole has been an administrative orphan, passed from one agency or unit to another about every ten to twenty years. Prior to 1910, the War Department had a limited involvement in the administration of the battlefield. From 1910 to 1933, the administration of Big Hole battlefield was shared between the War Department and the U.S. Forest Service. Since coming into the national park system in 1933, Big Hole has been assigned to regional offices in Omaha, Denver, Seattle, and San Francisco, while its unit managers have reported directly to superintendents of Yellowstone National Park, Grant-Kohrs Ranch National Historic Site, and Nez Perce National Historical Park. At different times the NPS has regarded Big Hole as coming within the political and recreational orbit of Yellowstone (as the nearest large national park in Montana), or within the interpretive orbit of Nez Perce Country, centered in Idaho. Frequent changes both in regional administrative boundaries and in thematic groupings of national park system units have impeded the smooth development of Big Hole's physical plant and management plans.