The Military Division of the Pacific was a major command (Department) of the United States Army during the late 19th century.
On July 27, 1865, the Military Division of the Pacific was created under Major General Henry W. Halleck, replacing the Department of the Pacific, consisting of the Department of the Columbia that now consisted of the state of Oregon and the territories of Washington and Idaho and the expanded Department of California that now consisted of the states of California and Nevada and the Territory of New Mexico and Territory of Arizona.
[1] Headquarters for the Division of the Pacific and the Department of California remained in the City of San Francisco.
From December 7, 1871, the one general officer at San Francisco commanded both the Division of the Pacific and the Department of California and the separate staffs were consolidated into one.
In June 1875, the part of the Territory of Idaho that lay east of the extension of the western boundary of Utah, and including Fort Hall, was detached from the Department of Columbia and added to the Department of the Platte.