Service number (United States Army)
In the nineteenth century, the Army also used pay records as a primary means of identifying service members after discharge.
The Army first began using service numbers (SNs) in 1918 as a result of the United States' involvement in World War I and the need for a record tracking system capable of indexing the millions of soldiers who were joining the ranks of the National Army.
As the strength of the National Army rose into the millions, this old method of muster rolls and rosters became outdated and a new system had to be developed.
The decision to create service numbers was made in February 1918, with the first service numbers to be issued only to Army enlisted personnel; the Army officer corps was still relatively small, and the U.S. Navy still maintained ship rosters to keep track of its personnel.
The U.S. Marine Corps and U.S. Coast Guard were also relatively small, and without the need for a service number system to track personnel.
Enlisted personnel who were World War I veterans continued to hold their pre-6 million series service numbers.
Officers of the Organized Reserve and National Guard received numbers in an arbitrary but generally-increasing manner in the range of 140 000 or higher, and in 1935, the Army extended this sequence to 499 999.
A subset of this series was reserved solely for enlistees from recruiting stations outside of the 48 contiguous U.S. states.
Prior to 1940, there was no procedure to issue service numbers to National Guard enlisted men, since most served completely under the authority of their state governments.
Guardsmen federalized from Hawaii were issued service numbers beginning with 20 01 while the 20 02 series was used by men from Puerto Rico.
The forty million series numbers were discontinued after World War II and never reused.
These numbers were rarely issued and the ninety million series was permanently discontinued after World War II.
At the same time, the Army added several other R series prefixes to deal with special enlisted situations.
At the end of the Second World War, the United States Army was reorganized into the following components: Between 1945 and 1947, the World War II draft force was slowly disbanded with the 30 and 40 million service number series formally discontinued.
Personnel who chose to remain on active duty kept their original service numbers, regardless of their new component.
The Regular Army service number system, ranging from 10 to 19 million, remained unchanged.
In 1954, one year after the close of the Korean War, the Army extended the range of officer service numbers by adding the three and four million series.
At the same time, there were still a wide variety of older enlisted numbers still active, ranging back to the thirty million series used during World War II.
After 1969, the Army completely converted to Social Security numbers for the identification of military personnel.
A comparison of the state codes between the Regular Army, World War II draft force, and Korea/Vietnam draft force is as follows: In 1940, when the United States Army expanded its service numbers beyond ten million, the range of 10 000 000 to 10 999 999 was reserved for Regular Army enlisted personnel who joined from recruiting stations outside the United States.
The remaining range of 11 000 000 to 19 999 999 was reserved for Regular Army personnel who enlisted from within the United States with the first two numbers a geographical code and the last six a personal identifier.
In general, both the Army and Air Force made every effort to avoid repeating service numbers although some mistakes did occur.
