U. S. V.

United States Volunteers also known as U.S. Volunteers, U. S. Vol., or U.S.V. were military volunteers enlisted in the United States Army who were separate from the Regular Army.

Starting as early as 1861 these regiments were often referred to as the Volunteer Army of the United States but not officially named (codified into law) that until 1898.

During the nineteenth century this was the United States federal government's main means for raising large forces of citizen-soldiers needed in wartime to augment the small Regular Army and organized militia and National Guard. The U.S. Volunteers were the forerunner of the National Army in World War I and the Army of the United States in World War II, the Korean War, and the Vietnam War.

The U.S. Volunteers did not exist in times of peace. Unlike the militia, which, under the United States Constitution, each state recruited, trained, equipped, and maintained locally, with regimental officers appointed and promoted by state governors and not kept in federal service for more than nine months nor sent outside the country, the U.S. Volunteers were enlisted for terms of one to three years, and between 1794 and 1902 fought outside the country.

Regiments and batteries became known as "Volunteers" to distinguish between state and regular army units.

The great majority of soldiers who served during the War of 1812 were volunteers, or members of state militia who were federalized for portions of the war period. There were also volunteer units directly raised by the federal government.

U.S. Volunteers were seen as "temporary regulars" because they were not state troops but rather augmented the Regular Army.

GENERAL ORDERS No. 15., WAR DEPARTMENT, Adjutant General's Office, Washington, May 4, 1861.

The President of the United States having called for a Volunteer Force to aid in the enforcement of the laws and the suppression of insurrection, and to consist of thirty-nine regiments of infantry and one regiment of cavalry, making a minimum aggregate of (34,506) thirty-four thousand five hundred and six officers and enlisted men, and a maximum aggregate of (42,034) forty two thousand and thirty-four officers and enlisted men, the following plan of organization has been adopted, and is directed to be printed for general information:...

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