--- title: "Part III, Subpart ii, Chapter 2, Section H Service Department Organizational Structures and Service Number Assignments" document: "M-21-1" section: "Part III, Subpart ii, Chapter 2, Section H" canonical: "https://veteranai.co/va-regulations/m21-1/iii.ii.2.h-service-department-organizational-structures-and-service" source: "https://www.knowva.ebenefits.va.gov/system/templates/selfservice/va_ssnew/help/customer/locale/en-US/portal/554400000001018/content/554400000037154/M21-1-Part-III-Subpart-ii-Chapter-2-Section-H-Service-Department-Organizational-Structures-and-Service-Number-Assignments" updated: "2026-09-07T14:37:08.393656Z" --- December 13, 2005 ### III.ii.2.H.1.a. Army Echelons and Appropriate Designations The table below lists the Army echelons and appropriate designations. | **Echelons** | **Designations** Army | Numerical/Geographical Corps | Roman numeral Division | Numerical by combat arm Brigade | Numerical or combat command, such as _Alpha_ Regiment | Numerical by combat arm Group | Numerical by combat arm Battalion | Numerical/battle group numerical/squadron numerical Company | Alpha/Battery - Alpha/Troop - Alpha Platoon | Numerical/Detachment – Numerical Squad | Numerical Fire Team | \--- ### III.ii.2.H.1.b. Availability of Organizational Records Rosters, morning reports, and sick reports may be available down to the company level. **Note:** The Army discontinued morning reports in 1974/1975. ### III.ii.2.H.1.c. Other Organizational Units that May Have Created Records Records, including clinical and medical records, may exist for other organizations and units, such as * garrison-type units, and * hospitals. **Important:** If a unit was considered independent from higher echelons, it may have created its own records. #### ## 2. Navy Organizational Structure This topic contains information on the Navy organizational structure, including * Navy echelons and appropriate designations * echelons for the * Naval Air Force * Naval Surface Force, and * Naval Submarine Force * ship designations, and * shore establishment organization. August 13, 2009 ### III.ii.2.H.2.a. Navy Echelon and Appropriate Designations The table below lists the Navy echelon and appropriate designations. For clarification, samples of unit designations are shown in italics. | **Echelon** | **Designations** Fleet-Atlantic Pacific | Numbered fleets Fleet | Numerical (_7 th Fleet; 7thFlt_.) Task force | Task force number and type of force (_CTF-45 Battle Force_) **Notes:** * Task forces are operational sub-units of fleets organized to perform specific missions for the fleet. * The following are Naval Task forces: * the Naval Air Force * the Naval Surface Force, and * the Naval Submarine Force. Fleet Marine Force | **Reference:** For more information on the Fleet Marine Force, see M21-1, Part III, Subpart ii, 2.H.4. U.S. Naval Forces Europe | \--- Middle East Force-Persian Gulf | \--- ### III.ii.2.H.2.b. Echelon for the Naval Air Force The following list shows the echelon for the Naval Air Force: * carrier strike group (_CSG 5_) * carrier air wing, and (_CVW-2_) * squadron (_VFA-2; VAQ-131_) **Notes:** * Carrier strike groups were historically designated carrier battle groups. * Carrier air wings were historically designated carrier air groups. ### III.ii.2.H.2.c. Echelon for the Naval Surface Force The following list shows the echelon for the Naval Surface Force: * flagship, and * Cruiser Destroyer Group Squadron (_CCDG-5; DESRON-23)_ **Note:** The Cruiser Destroyer Group Squadron consists of the Surface Group, Service Group Squadron, Amphibious Group Squadron, Mine Group Division, and Special Warfare Group. ### III.ii.2.H.2.d. Echelon for the Naval Submarine Force The following list shows the echelon for the Naval Submarine Force: * submarine group, and * submarine squadron (_SUBRON 11_) ### III.ii.2.H.2.e. Ship Designations Individual ships under the above echelons are identified as USS (name of ship) followed by an alpha-numerical hull number which * distinguishes the ship from other ships with the same name that may have preceded or may have followed it, and * identifies the type of ship. **Example:** USS Independence CVA-62. ### III.ii.2.H.2.f. Shore Establishment Organization Shore establishments, such as non-moveable shore installations, were organized as bureaus (technical in nature) that, with the exception of personnel and medicine and surgery, became the Naval material command in 1963. Other system type commands have followed this tradition. #### ## 3. Air Force Organizational Structure This topic contains information on the Air Force organizational structure, including * Air Force echelons and appropriate designations * availability of organizational records, and * other organizational units that may have created records. December 13, 2005 ### III.ii.2.H.3.a. Air Force Echelon and Appropriate Designations The table below lists the echelon of Air Force units and appropriate designations. | **Units** | **Designations** Command | Geographical/specified mission Air force | Numerical/geographical Air Division | Numerical Wing | Numerical/specified mission Group | Numerical/specified mission Squadron | Numerical/specified mission/alpha Flight | Numerical—Alpha ### III.ii.2.H.3.b. Availability of Organizational Records Other organizational records may be available, such as * medical records * rosters * morning reports * courts martial, and * academic records. **Notes:** * Some records may have a limited retention period. * Academic records dated after 1967 may be obtained from another National Archives and Records Administration center, if still retained. * Morning reports were discontinued in June 1966. ### III.ii.2.H.3.c. Other Organizational Units That May Have Created Records Records, including clinical and medical records, may exist for other organizations and units, such as * agency center * hospital * office * service, and * academy. #### ## 4. Marine Corps Organizational Structure This topic contains information on the Marine Corps organizational structure, including * Marine Corps echelons and appropriate designations * division echelons, and * availability of organizational records. January 5, 2017 ### III.ii.2.H.4.a. Marine Corps Echelons and Appropriate Designations The table below lists the Marine Corps echelons and appropriate designations. For clarification, samples of unit designations are shown in italics. | **Echelon** | **Designation** Fleet Marine Force | Atlantic/Pacific (_FMFPac_) Marine Amphibious Force **Note:** Consists of the * Marine Division * Marine Aircraft Wing, and * Marine Logistics Group * historically, Force Service Support Group, and * counterpart, Marine Wing Support Group. | Roman numeral (_I MAF_) (operational) Division **Note:** Major sub-elements consist of * regiments, and * battalions. | Numerical (_3rdMarDiv_) **Reference:** For more information on the echelons of a division, see M21-1, Part III, Subpart ii, 2.H.4.b. Wing **Note:** Major sub-elements consist of * groups, and * squadrons. | Numerical (_1stMAW_) **Note:** Squadrons are designated alpha-numerically. (_VMA-211; HMM-262_) Marine Expeditionary Force (MEF) **Note:** Marine Air ground task force for operations and exercises which consists of the * Marine Division * Marine Aircraft Wing, and * Marine Logistics Group. | Roman numeral (_III MEF_) Marine Expeditionary Brigade (MEB) **Note:** Marine Air ground task force for operations and exercises which consists of the * Regimental Landing Team * Composite Aircraft Group, and * Combat Logistics Regiment. | Numerical (_3d MEB_) Marine Expeditionary Unit (MEU) **Note:** Marine Air ground task force for operations and exercises which consists of the * Battalion Landing Team * Composite Aircraft Squadron, and * Combat Logistics Battalion | Numerical (_31 MEU_) **Notes:** * _Expeditionary_ units replaced historically designated _amphibious_ units. * _Logistics_ units replaced historically designated _force service support_ units. ### III.ii.2.H.4.b. Division Echelons The table below lists the Marine Corps division echelons and appropriate designations. | **Echelon** | **Designation** Regiment | Numerical (_7 th Marines; 7th Mar._) Battalion | Numerical (_2 nd Battalion; 2nd Bn_) Company | Alpha or phonetic (_D Company; Delta Co_.) Platoon | Numerical (_1 st Platoon; 1st Plt_.) Squad | Numerical (_3 rd Squad; 3rd Sqd_.) ### III.ii.2.H.4.c. Availability of Organizational Records The organizational records listed below are available for the years shown. * Muster rolls are available for the years 1801 through present. * Indexes are available for the years 1897 through 1939. * Unit diaries are available for the years 1949 through 1964. * Bound diaries are available back to 1901. **Notes:** * Unit diaries have been microfilmed and are stored on the 5th floor of the National Personnel Records Center (NPRC). These unit records may include * command chronologies * operational situation reports (sitreps), and * operation after-action reports. * Some individual reels may be unusable due to poor storage conditions. * Marine Corps headquarters maintains duplicate copies of the unit diaries. * Many Marine Corps unit records are stored on compact discs (CDs) and accessed via the [Stressor Verification]() page. **Reference:** For more information on accessing these records, see * the Veterans Benefits Administration broadcast transcripts of * December 17, 2003, “[Researching Marine Corps Records](),” and * May 18, 2004, “[C&P Military Records Research Information](),” and * [M21-1, Part III, Subpart ii, 2.E.6.d](). #### ## 5. Guide for Service Numbers 1 through 9,999,999 This topic contains a guide to service numbers 1 through 9,999,999, including * Army service numbers * Navy service numbers * Marine Corps service numbers, and * Coast Guard service numbers. July 23, 2018 ### III.ii.2.H.5.a. Army Service Numbers The table below lists the numbers used for Army enlisted personnel for the periods shown. **Notes:** * The Army originally assigned Air Force service numbers lower than 10,000,000. * Omitted blocks of numbers were not assigned. | **Series** | **Dates Assigned** 1 through 5,999,999 | 1918 through 1919 6,000,000 through 7,999,999 | 1919 through 1940 8,000,000 through 8,999,999 | 1948 and after (for Women only) ### III.ii.2.H.5.b. Navy Service Numbers The table below lists the numbers used for Navy enlisted personnel for the periods shown. | **Series** | **Dates Assigned** 1,000,000 through 1,999,999 | 1885-1918 2,000,000 through 9,999,999 | 1918-1965 100,000 and higher (Letter Prefix) | 1965 and after ### III.ii.2.H.5.c. Marine Corps Service Numbers The table below lists the numbers used for Marine Corps enlisted personnel for the periods shown. | **Series** | **Dates Assigned** 20,000 through 99,999 | 1905 through 1917 100,000 through 349,999 | 1917 through 1941 350,000 through 670,899 | 1941 through 1947 700,000 through 799,999 | reserved for female enlisted personnel only 800,000 through 999,999 | 1943 through 1947 1,000,000 through 1,699,999 | 1944 through 1957 1,700,000 through 1,799,999 | reserved for female enlisted personnel only 1,800,000 through 1,999,999 | 1956 through 1965 2,000,000 and higher | 1964 and after ### III.ii.2.H.5.d. Coast Guard Service Numbers The table below lists the numbers used for Coast Guard enlisted personnel for the periods shown. | **Series** | **Dates Assigned** 100,000 through 199,999 | through 1930 200,000 through 254,999 | 1930 through 1942 255,000 through 349,999 | 1945 through 1962 350,000 through 499,999 | 1962 until 1974 500,000 through 999,999 | 1941 through 1945 2,000,000 through 2,199,999 | 1948 through 1974 ## 6. Guide for Service Numbers 10,000,000 through 19,999,999 December 13, 2005 ### III.ii.2.H.6.a. Regular Army and Regular Air Force Enlisted Service Numbers The table below lists the numbers used for regular Army and regular Air Force enlisted personnel for the periods shown. **Notes:** * Series 10,000,000 through 10,999,999 are used for initial enlistments occurring outside the continental limits. * The Army originally assigned Air Force service numbers lower than 10,000,000. | **Series** | **Dates Assigned** 10,000,000 through 10,999,999 | 1940 and after 11,000,000 through 11,142,500 | 1940 through 1945 11,142,501 through 11,188,000 | 1946 through 1948 11,188,001 through 11,238,500 | 1949 through 1951 11,238,501 through 11,283,000 | 1952 through 1954 11,283,001 through 11,344,500 | 1955 through 1957 11,344,501 through 11,384,000 | 1958 through 1960 11,384,001 through 11,999,999 | 1961 and after 12,000,000 through 12,242,000 | 1940 through 1945 12,242,001 through 12,321,000 | 1946 through 1948 12,321,001 through 12,393,500 | 1949 through 1951 12,393,501 through 12,469,000 | 1952 through 1954 12,469,001 through 12,553,375 | 1955 through 1957 12,553,376 through 12,614,900 | 1958 through 1960 12,614,901 through 12,999,999 | 1961 and after 13,000,000 through 13,197,500 | 1940 through 1945 13,197,501 through 13,299,700 | 1946 through 1948 13,299,701 through 13,408,700 | 1949 through 1951 13,408,701 through 13,511,500 | 1952 through 1954 13,511,501 through 13,621,140 | 1955 through 1957 13,621,141 through 13,705,500 | 1958 through 1960 13,705,501 through 13,999,999 | 1961 and after 14,000,000 through 14,204,500 | 1940 through 1945 14,204,501 through 14,300,770 | 1946 through 1948 14,300,771 through 14,454,000 | 1949 through 1951 14,454,001 through 14,547,500 | 1952 through 1954 14,547,501 through 14,661,000 | 1955 through 1957 14,661,001 through 14,745,000 | 1958 through 1960 14,745,001 through 14,999,999 | 1961 and after 15,000,000 through 15,201,000 | 1940 through 1945 15,201,001 through 15,280,500 | 1946 through 1948 15,280,501 through 15,465,760 | 1949 through 1951 15,465,761 through 15,530,600 | 1952 through 1954 15,530,601 through 15,593,615 | 1955 through 1957 15,593,616 through 15,639,615 | 1958 through 1960 15,639,616 through 15,999,999 | 1961 and after 16,000,000 through 16,201,500 | 1940 through 1945 16,201,501 through 16,307,000 | 1946 through 1948 16,307,001 through 16,398,890 | 1949 through 1951 16,398,891 through 16,481,925 | 1952 through 1954 16,481,926 through 16,600,497 | 1955 through 1957 16,600,498 through 16,638,100 | 1958 through 1960 16,683,101 through 16,999,999 | 1961 and after 17,000,000 through 17,183,500 | 1940 through 1945 17,183,501 through 17,254,500 | 1946 through 1948 17,254,501 through 17,338,810 | 1949 through 1951 17,338,841 through 17,410,300 | 1952 through 1954 17,410,301 through 17,512,785 | 1955 through 1957 17,512,786 through 17,592,940 | 1958 through 1960 17,592,941 through 17,999,999 | 1961 and after 18,000,000 through 18,247,100 | 1940 through 1945 18,247,101 through 18,360,800 | 1946 18,360,801 through 18,546,000 | 1947 through 1957 18,546,001 through 18,607,725 | 1958 through 1960 18,607,726 through 18,999,999 | 1961 and after 19,000,000 through 19,235,500 | 1940 through 1945 19,235,501 through 19,324,485 | 1946 through 1948 19,324,486 through 19,420,000 | 1949 through 1951 19,420,001 through 19,520,770 | 1952 through 1954 19,520,771 through 19,590,665 | 1955 through 1957 19,590,666 through 19,597,661 | 1958 19,597,662 through 19,999,999 | 1959 and after ## 7. Guide for Service Numbers 20,000,000 and Higher December 13, 2005 ### III.ii.2.H.7.a. Service Numbers 20,000,000 and Higher The table below lists the service numbers 20,000,000 and higher, the time periods in which they were issued, and the service categories to which they were issued. | **Series** | **Period Issued** | **Service Category** 20,000,000 through 20,999,999 | 1940 through 1946 | Enlisted National Guard in active duty. 21,000,000 through 29,999,999 | 1946 and after | Enlisted National Guard of the U.S. 30,000,000 through 39,999,999 | 1940 through 1946 | Enlisted personnel inducted into the Army of the U.S. 40,000,000 through 41,999,999 | \--- | Apparently not used or allocated. 42,000,000 through 46,999,999 | 1943 through 1946 | Enlisted personnel inducted into the Army of the U.S. 47,000,000 through 49,999,999 | \--- | Apparently not used or allocated. 50,000,000 through 59,999,999 | 1948 through 1966 | Army and Air Force Emergency Interim Issue (EM). **Note:** Regular Army and Air Force are not included. 60,000,000 through 69,999,999 | 1966 and after | Army and Air Force EM. **Note:** Regular Army and Air Force are not included. 70,000,000 through 89,999,999 | \--- | Apparently not used or allocated. 90,000,000 through 99,999,999 | 1940 through 1945 | Only a limited number, about 20,000 within this series, were used for the Philippine Army during World War II. **Note:** There is no evidence of other usage.