UNITED STATES ARMY ORGANIZATION IN THE
WESTERN UNITED STATES, 1846-1891
By the time Brig. Gen. Stephen Watts Kearny, marching overland from his victory
at Santa Fe, arrived in California in December 1846, the War Department had
divided the United States and the territories into the Eastern and Western
Divisions with ten military departments under them. The Western Division's
Military Departments 9 and 10, created on November 3, 1846, administered the
territory recently acquired from Mexico:
Military Department 9 – To embrace so much of the Mexican province of New Mexico
as has been
or may be subjected to the arms or the authority of the United States.
Military Department 10 – To consist of the Territory of Oregon and so much of
the Mexican
provinces of the two Californias as has been or may be subjected to the arms or
the authority of the
United States.
On February 9, 1847, General Kearny assumed command of Military Department 10
and established his headquarters at Monterey. At the same time he became the
military governor of California.
The Army completely reorganized its administrative machinery on August 31, 1848,
establishing nine
military departments in the Eastern and Western divisions, and two independent
military departments, 10 and 11. These two reported directly to the War
Department:
Military Department 10 – California. Headquarters at Monterey.
Military Department 11 – Oregon Territory. Headquarters at Fort Vancouver on the
Columbia
River.
Later that year, on October 10, 1848, Departments 10 and 11 were assigned to a
newly created Pacific Division that also had its headquarters at Monterey. In
1849 the commanding general moved the division headquarters to the City of San
Francisco, but only for one month. In July they moved to Benicia where they
remained for the next two years.
On May 17, 1851, both military departments merged into the Pacific Division and
ceased to exist as such. The division headquarters then directly administered
military affairs on the West Coast (California and Oregon Territory). A year
later, on June 15, 1852, Pacific Division headquarters moved from Benicia back
to the City of San Francisco where it remained for two years.
On October 31, 1853, the Army abandoned the system of divisions and numbered
departments and
established five new departments each having a descriptive name, each department
reporting directly to Headquarters of the Army. At San Francisco the Department
of the Pacific headquarters administered military affairs in the county west of
the Rocky Mountains, except Utah Territory and the Department of New Mexico,
i.e., New Mexico Territory east of the 110th meridian.
On September 2, 1854, the Department of the Pacific headquarters again packed
its bags and returned to Benicia where it remained until January 1857. This
revolving door closed on that date when the headquarters returned to the City of
San Francisco where it remained for many years to come.
On January 14, 1858, the Department of the Pacific gained the Territory of Utah
west of the 117th meridian from the Department of Utah (i.e., western Nevada).
Reorganization continued. On September 13, 1858, the Department of the Pacific
came to an end. In its
place rose two new departments, each reporting directly to army headquarters:
Department of California – The country west of the Rocky Mountains and south of
Oregon and
Washington territories, including the Rogue River and Umpqua districts of
Oregon, and excluding
Utah east of the 117th meridian and New Mexico east of the 110th. Headquarters
remained at San
Francisco.
Department of Oregon – Oregon and Washington territories, except Rogue River and
Umpqua
districts.
On January 15, 1861, as the nation neared civil war, the Army revived the
Department of the Pacific by consolidating the Departments of California and
Oregon and retaining the headquarters at San Francisco. When Brig. Gen. George
Wright became the department commander in October 1861, he found that San
Francisco's climate aggravated his asthmatic condition and he hoped to move the
headquarters to Sacramento. It appears, however, that the headquarters remained
at San Francisco while General Wright spent considerable time at Sacramento.
During the war, from 1863 to 1865, the Department of the Pacific had five
districts: California, Oregon,
Humboldt, Utah, and Southern California.
In July 1865 the Department of the Pacific was abolished and was replaced by the
Departments of California and the Columbia. The Department of California, with
its headquarters at San Francisco, was composed of California, Nevada, and
Arizona Territory.
A month later, August 30, 1865, the Army established the Military Division of
the Pacific that embraced California, Oregon, Nevada, and the Territories of
Arizona, Washington, and Idaho. It contained two departments:
Department of California – California, Nevada, and Arizona Territory (and,
briefly, New Mexico).
Department of the Columbia – Oregon and the Territories of Washington and Idaho.
Headquarters for the Division of the Pacific and the Department of California
remained at the City of San Francisco. On March 18, 1868, the Army established
the Department of Alaska and placed it under the Division of the Pacific. This
department, however, was discontinued on July 1, 1870, and Alaska was absorbed
by the Department of the Columbia.
The Department of Arizona was established under the Division of the Pacific on
April 15, 1870. It consisted of Arizona Territory and California south of a line
from the northwest corner of Arizona to Point Conception so as to include Los
Angeles and San Diego. (Although the Department of Arizona lost Southern
California
on February 14, 1883, it regained that part of California south of the 35th
parallel on December 15, 1886.)
Beginning December 7, 1871, the one general officer at San Francisco commanded
both the Division of the Pacific and the Department of California and the former
separate staffs were consolidated into one. In June 1878 the Congress authorized
the Division of the Pacific headquarters to move from San Francisco to the
Presidio of San Francisco. This event took place on July 1.
On November 30, 1885, the Territory of New Mexico transferred from the
Department of the Missouri to the Department of Arizona, thus coming under the
Division of the Pacific.
Early in 1887 the headquarters of the Division of the Pacific, having failed to
secure an appropriation for a suitable administration building, moved from the
Presidio of San Francisco back to the City of San Francisco. The Military
Division of the Pacific was discontinued on July 3, 1891, and each of the three
departments:
Arizona, California, and the Columbia – then reported directly to the War
Department. The Department of California, with its headquarters at San
Francisco, consisted of California north of the 35th parallel and Nevada.
Early in 1887 the headquarters of the Division of the Pacific, having failed to secure an appropriation for a suitable administration building, moved from the Presidio of San Francisco back to the City of San Francisco. The Military Division of the Pacific was discontinued on July 3, 1891, and each of the three departments:
Arizona, California, and the Columbia – then reported directly to the War
Department. The Department of California, with its headquarters at San
Francisco, consisted of California north of the 35th parallel and Nevada
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