Navy officer service numbers were simple in design since the Navy officer corps in 1920 was relatively small and there was little need for a complex service number system. The first Navy service numbers, which ranged from 1 to 500, were designated for retroactive presentation to retired naval officers who had served in the First World War and prior. There was much discussion within the Navy as to which Navy officer should receive Navy service #1, with suggestions ranging from
George Dewey to
John Paul Jones. In the end, the Navy never proceeded with the retroactive presentation of officer service numbers and the first five hundred numbers remained un-issued. The service numbers 501 to 999 were reserved for officers who were then serving on active duty in 1920. The first thirty service numbers (501 – 531) were issued but never recorded. It is possible that these were retroactive but the Navy did not keep records of which officers held these numbers. The first service number of file was #532 which was issued to Samuel R. Colhoun who was a
Captain in the
Navy Supply Corps with service in both the
Spanish–American War and the
Civil War. The Navy continued to issue further service numbers to other officers based on seniority within the Navy. In 1922, the Navy extended the service number range of officers to 10,000 and by 1925 had extended the range again to 100,000. The issuance of service numbers was based simply by date of commission within the Navy; by 1929, the Navy saw the need to extend this range again to 125,000. The cap of 125,000 had just barely been reached by the outbreak of World War II in 1941. During the Second World War, Navy officer service numbers were extended to 350,000; these numbers were simply issued by entry date into the Navy officer corps without regard to membership in the Regular Navy or
United States Navy Reserve. In 1945, with the service number cap now reached, the Navy extended officer service numbers again to 600,000. It was not until 1955, after the Korean War had ended, that a need arose for continued expansion of Navy officer numbers. The new Navy officer numbers now extended to a cap of 800,000; service numbers had reached #670,900 by the year 1963. In 1971, with the service number cap of 800,000 nearly reached, the Navy extended officers numbers one final time to 999,999 which the Navy felt would cover all future officers to the end of the 20th century. Only a handful of numbers above 800,000 were ever issued and the Navy discontinued service numbers in January 1972. ==Navy enlisted service numbers==