Table of Contents
Pacific Division of the U. S. Army
This Army Division was one of its superior administrative organizations that existed during the early 19th century and for a short time in the early 20th century. The U.S. Army’s Pacific Division was headquartered in this building, the Leese-Fritch House. General Persifor Smith coordinated affairs of California and Oregon Departments from here 1849-50
The first Pacific Division of the U.S. Army was created on October 10, 1848, as the Army reorganized its administration for the new territories acquired during the Mexican–American War. 10th Military Department (California) and 11th Military Department (Oregon Territory) were subordinated to the new Division that had its headquarters at Monterey. In June 1849 division headquarters moved to the California, for a month then moved to Benicia and the Benicia Arsenal in the upper San Francisco Bay in July 1849.
On May 17, 1851, the Army merged Military Departments 10 and 11 into the Pacific Division as the Army again reorganized its administration on the West Coast. Both of those military departments merged into the Pacific Division ceased to exist. Division headquarters directly administered affairs in California and Oregon Territory. On June 15, 1852, Pacific Division headquarters was moved from Benicia to San Francisco.

On October 31, 1853, the Pacific Division was replaced by the Department of the Pacific, with headquarters in San Francisco. It was created when the Army abandoned the system of divisions and numbered departments, establishing departments having a descriptive name, and reporting directly to Army Headquarters.
Commanders of the Pacific Division
- Major General Persifor Frazer Smith October 10, 1848–1849
- Brevet Major General Bennet Riley 1849–1851
- Brevet Brigadier General Ethan A. Hitchcock 1851–1853
Sonoma Barracks, Sonoma, 1847–1852
The history of the Barracks gets its start as the Mission San Francisco Solano (1823) and it was the last mission established by the Franciscans in Alta California. The Mexican Army took control of the mission in 1836 and fortified the compound in an effort to thwart Russian and American traders from the northern coast. This location was the northernmost limit of Mexican control. The compound was captured by independent Californians in June 1846, and with this capture was the start of the “Bear Flag Revolt”.
The U.S. Army gained control in July 1846. It was renamed Sonoma Barracks in 1847. Sonoma Barracks was used by the U.S. Army until 1852. Located at Spain Street East and 1st Street East. The history of the Sonoma Barracks is immensely significant. It not only represents an important headquarters of multiple military units under three flags, including the first American government in all of California, but it’s also where the prototype of California’s most recognizable symbol – its flag with a grizzly bear – was created.
READ – Gibbs’ Party Time While in the Pacific Division.
Barracks Slideshow
The significance of Sonoma Barracks 1847–1852
The Sonoma Barracks, located in the town of Sonoma in northern California, were built in 1847 as a military installation by the Mexican government (Sonoma Barracks State Historic Park, n.d.). They were used by the Mexican Army to help maintain order in the region and to defend against potential threats from Native American tribes and foreign powers (Sonoma Barracks State Historic Park, n.d.).
In 1848, the United States claimed California as part of the Treaty of Guadalupe Hidalgo, which ended the Mexican-American War (National Archives, n.d.). The Sonoma Barracks were subsequently occupied by U.S. military forces, who used them as a base of operations during the California Gold Rush (Sonoma Barracks State Historic Park, n.d.).
During this time, the Barracks played a significant role in the history of California and the United States. They served as the headquarters for the U.S. military in northern California and were the site of several important events, including the Bear Flag Revolt and the establishment of the California Republic (Sonoma Barracks State Historic Park, n.d.).
The Barracks were decommissioned in 1852 and are now a state historic park (Sonoma Barracks State Historic Park, n.d.). They are open to the public and provide a glimpse into the history of California and the role that the military played in the development of the state (Sonoma Barracks State Historic Park, n.d.).
References:
- National Archives. (n.d.). Treaty of Guadalupe Hidalgo. Retrieved December 25, 2022, from https://www.archives.gov/education/lessons/guadalupe-hidalgo
- Sonoma Barracks State Historic Park. (n.d.). History. Retrieved December 25, 2022, from https://www.parks.ca.gov/?page_id=479