Military Records

Naval Attaché Reports During the World War 2 Era

“It has always been the fundamental principle of the naval attaché detail that the officer selected should come to Washington for temporary duty in the Office of Naval Intelligence, and, by looking over the files, visiting all the technical bureaus of the Navy Department, and various shipyards and shipbuilding plants, put himself quite up-to-date in all matters relating to the progress in personnel and material in our own country, and in the United States Navy in particular.”

Confidential, Secret, and Top Secret Naval Attaché Reports 1940-1947

The Confidential, Secret, and Top Secret Naval Attaché reports are a uniquely arranged record collection that prove difficult to access for both new and experienced researchers. These records are valuable resources for researchers looking for information on a wide range of World War II era topics regarding military and non-military subjects. These reports contain various types of information, such as compilations of unanalyzed data, casual remarks of foreign diplomats, descriptions of foreign naval forces, monographs of social or political troubles in foreign countries, interviews with paid informants, escapees, defectors, and prisoners of war, maps, and photographs of ships and aircrafts. These are but a few of the diverse subjects these intelligence reports contain.

Record Group 38: Records of the Office of the Chief of Naval Operations

Entry A1 98-A, Series: Confidential Reports of Naval Attachés 1940-1946

Entry A1 98-B, Series: Secret Reports Of Naval Attachés 1940-1946

Entry A1 98-C, Series: Top Secret Reports of Naval Attachés 1944-1947

Entry A1 98-D, Series: Photostatic Copies of German Submarine Records 1941

Entry A1 95-A, Series: Index to Secret and Confidential Reports of Naval Attachés

Entry M1332, Series: Duplicating Microfilm of Entry A1 95-A, Subject Index to Naval Intelligence Reports, 1940-1946.

During the World War 2 era, a primary goal of the Office of Naval Intelligence was to collect and record naval information that may be useful to the Department of the Navy in times of war, as well as in times of peace. This includes information about the organization, strength, tactics, technology, equipment, and personnel of foreign military forces. However, it also includes collecting information on political, economic, and social conditions in foreign countries. Naval Attachés serve as members of U.S. diplomatic missions and collect their information from a variety of sources, such as technical documents, publications, newspapers, press reports, contacts with foreign businesses, political debates, confidential sources, and observations.

The Confidential Naval Attaché Reports (Entry A1 98-A) is arranged into three subsections. The first subsection (boxes 1-1276) is arranged by an alpha-numeric subject identifier, followed by the report register number, and finally, the title of the report. The alpha-numeric subject identifier is simply a code indicating a broad or specific subject. The designation consists of a letter, then a number, followed by another letter. For example, if you are interested in reports on national flags, the alpha-numeric subject identifier you will reference is A-3-a. If you are interested in researching reports on chemical warfare, you will reference reports with the subject identifier F-1-g. Some subjects occupy several alpha-numeric identifiers. For instance, reports on ammunition and equipment have the subject identifiers A-2-a through A-2-g. Likewise, reports on armor have the subject identifiers A-7-a through A-7-c. A partial list of these alpha-numeric subject identifiers can be found in the partial subject guide below.

The second section of confidential reports (boxes 1277-1349) is arranged by geographic location. However, the geographic locations are not arranged alphabetically. These reports come from Naval Attachés and other Navy commands in various locations around the world. Unlike the previous section of reports, these reports do not use the alpha-numeric subject identifiers. Instead, after the name of the location is a numeric arrangement, starting at 1 and increasing upward, followed by the number 46. For example, reports from the Naval Attaché in Paris start at 1/46 and end at 753/46.

The third subsection of the confidential reports consists of a collection of reports that were previously withdrawn because they contained information that continued to be classified after the rest of the Series was declassified. When going through boxes in the first two subsections, you may find withdrawal cards, indicating that a specific file has been withdrawn. This withdrawal card provides the alpha-numeric subject identifier, the report register, and the title of the report that was withdrawn. All of these reports were withdrawn when the Series was declassified. Eventually, the withdrawn reports were declassified and added to the final ten boxes (numbered boxes 1-10).

The Secret Reports of Naval Attachés (Entry A1 98-B) is arranged strictly by the alpha-numeric subject identifier, report number, and title of the report. This is the same format as seen in the first subseries of the Confidential Naval Attaché Reports discussed above. Also note that the secret reports contain a section of 15 microfilm reels.

The Top Secret Reports of Naval Attachés (Entry A1 98-C) is arranged into three subsections. The first subsection is arranged numerically by document number (reports 30 to 4082). The second subsection consists of enclosures to the first subsection and is arranged by serial numbers (Serial X652 through Serial 147-TS-44). The third subsection consists of unarranged documents.

The Photostatic Copies of German Records and Publications (Entry A1 98-D) includes German submarine records, patent publications, and farmer association journals. These records are generally arranged in chronological order. Initially these records were included with the records series Intelligence Division Naval Attaché Reports, 1886-1939 (Entry NM-63 98), but have been reallocated based on the date of the records. 

 To begin your research on Confidential and Secret Naval Attaché reports, we recommend consulting the record series index. The Index to Secret and Confidential Reports of Naval Attachés, 1940-1946 has been digitized from NARA Microfilm Publication M1332) and made available on the National Archives Catalog. This index consists of microfilmed index cards, arranged alphabetically by subject (Aeronautics to War Operations) which provide the alpha-numeric subject identifier, date of creation, summary of contents, and report number.

When reviewing the index cards look for key identifiers, for example the File designator (aka alpha-numeric designator) and the Register Number. This information will assist you in locating the corresponding documents. In the example below, the alpha-numeric designator is “B-6-d” and the Register Number is “20878.” 

refer to caption

Our example card can be found here in the microfilmed index and the information for the corresponding document in our catalog is located here.

Once you have located index cards that identify reports of interest, use the key identifiers, such as the alpha-numeric identifier and subject information, to find the corresponding report on our catalog. Our catalog will provide the Record Group, Entry, and box number (container number). With this information, you can request the reports for review in our research room in College Park, Maryland during a research visit, or use the information to request a reproduction order.

Subject Guide to Naval Attachés Reports 

Below is a partial subject guide to the Naval Attaché Reports. While this guide does not include all of the alpha-numeric subject identifies, the guide does identify broad categories and the corresponding alpha-numeric subject identifier. Using this partial subject can assist you in narrowing your research to a specific subject identifier or a range of subject identifiers. 


A-1: Aeronautics

A-1-a to A-1-g: Miscellaneous Information

A-1-h: Accidents and Casualties

A-1-i: Aeroplanes, General Data Factories (Types)

A-1-j: Armor and Armament

A-1-k: Balloons; Kites; Flares

A-1-l: Bases--Location and Equipment

A-1-m: Bomb Dropping and Bombs

A-1-n: Communications

A-1-o: Defenses, Ashore; Naval

A-1-p: Dirigibles

A-1-q: General Information (by Country); Helicopters; Instruments

A-1-r: Motors

A-1-s: Organization (Air Strength by Countries)

A-1-u: Personnel

A-1-v: Aerial Photography

A-1-w: Rules and Regulations

A-1-x: Scientific Investigation

A-1-y: Seaplanes; Carriers

A-1-z: War Operations

A-2-a to A-2-g: Ammunition and equipment

A-3-a: National Flags

A-4-a to A-6-c: Armies

A-7-a to A-7-c: Armor

A-8-a to A-8-e: Arts and Sciences--Engineering, Marine

A-9-a: Arts and Sciences--Chemistry

A-10-c: Arts and Sciences--Electricity

A-11-a: Arts and Sciences--Engineering, Civil and Military

A-11-c: Arts and Sciences--Explorations

A-12-a to A-12-g: Arts and Sciences--Manufacturing

B-2-a to B-2-e: Arts and Sciences--Navigation; Naval Construction

B-4-a to B-4-e: Arts and Sciences--Ordnance

B-4-h: Arts and Sciences--Scientific Investigation

B-4-k: Camouflage

F-1-g: Chemical Warfare

B-5-a to B-7-c: Commerce

B-7-e to B-10-e: Communications--by Nation

B-10-f: Communications--Air Routes

B-10-g: Communications--Cables

B-10-h: Communications--Canals and Inland Waterways

B-10-i: Communications--Radio

B-10-j to B-10-s: Communications--Railroads (by Continents)

B-10-t: Communications--Roads and Trails

B-10-u to B-10-x: Communications--Steamship Lines

B-10-y: Communications--Telephone and Telegraph

B-11-A to C-4-a: Depots and Bases (Army and Navy; Arsenals, etc.) (Diplomacy and Societies Changed to Relations and Policies; Societies)

C-11-b to D-11-c: Finances

E-10-a to E-10-c: Fueling and Fuel

E-10-m to E-10-n: Guide Books

E-11-a to E-12-e: Guns

F-1-a: Gun Carriages

F-2-a to F-4-d: Machinery

F-4-m: Meteorology; Names and Addresses

F-4-w to F-5-c: Operations, Army (Campaigns, Maneuvers, Movements, Plans of Campaigns)

F-7-c to F-10-e: Peace Operations, Naval

E-1-a to E-9-d: Personnel

F-11-b to F-11-e: Plans--Maps and Charts, Ordnance, Ships and Boats, Structures, Submarines, Torpedo Boats

F-11-m: Population--Movements; Numbers

H-1-a to N-1-b: Ports (by Countries) (Information Re Various Cities, etc.)

O-1-a to O-1-b: Provisions and Clothing

O-1-d: Radio Sets

O-1-g to O-1-l: Resources

C-8-a to C-10-n: Relations and Policies: All Nations Countries A to Z (Foreign and Domestic

O-1-m to P-4-c: Ships (by Nations)

P-5-a: Ships, Auxiliary

P-10-a to P-10-c: Signals and Signaling

P-11-e: Smoke Screens

C-6-a to C-6-e: Societies

P-10-d to P-10-n: Submarines

P-11-a to P-11-d: Strategy and Tactics (Now under Peace Operations)

R-1-a: Supplies

R-2-a to R-4-a: Target Practice

R-5-a to R-7-a: Torpedoes

R-8-a to R-11-c: Torpedo Craft

F-5-d to F-7-b: War Operations

U-1-a to U-4-b: Secret and Confidential Information--Various Subjects

Early World War 2 Era Naval Attaché Reports

The Record Entries highlighted above contain the bulk of the World War 2 era Naval Attaché records. However, Entry NM-63 98, Series: Intelligence Division Naval Attaché Reports, 1886-1939 is also worth noting. This Record Entry contains the Naval Attaché records leading into the World War 2 era and will provide additional context for many of the Record Entries listed above. Additionally, Entry M975, Series: Selected Naval Attaché Reports Relating to the World Crisis, 1937-1943 is digitized and highlights records of importance during the pre-war and early war time. This series identifies reports received from naval attachés on duty in foreign capitals. These reports provide information, observations, and estimates of technical matters relating to military strength, preparedness, and political and diplomatic affairs for the period before World War II and during the early stages of the conflict. It contains three main parts. The first subseries consists of "Berlin - War Diary, Sept 1, 1939-Mar 24, 1941." The second subseries consists of "Estimate of Potential Military Strength: Reports From London, Paris, Brussels, Rome, Berlin, Moscow and Tokyo; and Summaries, 1937-1943." The third subseries consist of "Probability of an Outbreak of War: Reports from London, Brussels, Rome, Berlin, Moscow, and Tokyo; and Summaries, 1936-1943." 

Continuing Research:

The Naval Attaches have been an important part of the Office of Naval Intelligence since the Office’s inception in 1882. While the collections referenced above primarily focus on the Naval Attaches during the World War 2 era, there are several additional collections specifically relating to Naval Attaches within the National Archives’ records holdings. We have identified several of these collections below and we linked each collection to our Catalog to facilitate learning more about the records. These collections are primarily held at the National Archives in Washington, DC and at the National Archives in College Park, MD. When planning a research visit, please note where each collection is held prior to visiting a National Archives facility. 


Entry A1 98-A, Series: Confidential Reports of Naval Attachés 1940-1946

Entry A1 98-B, Series: Secret Reports Of Naval Attachés 1940-1946

Entry A1 98-C, Series: Top Secret Reports of Naval Attaches 1944-1947

Entry A1 98-D, Series: Photostatic Copies of German Submarine Records 1941

Entry A1 95-A, Series: Index to Secret and Confidential Reports of Naval Attachés

Entry M1332, Series: Duplicating Microfilm of Entry A1 95-A, Subject Index to Naval Intelligence Reports, 1940-1946.

Entry NM-63 99, Series: Secret Naval Attache's Reports, 1936-43

Entry M975, Series: Selected Naval Attache Reports Relating to the World Crisis, 1937-1943 (This Entry is Duplicating Microfilm of Entry NM-63 99)

Entry A1 1006, Series: Correspondence and Reports from Naval Attaches, 1947-1953

Entry A1 1007, Series: Naval Attache Collection Plans and Related Correspondence, 1950-1953

Entry UD 3, Series: Correspondence with Naval Attaches, Observers, and Liaison Officers, 1930-1948

Entry UD 23, Series: Library, District Intelligence Officer [DIO], Attache and War College Training Records, 1945-1947

Entry UD-12D 2, Series: Logbooks and Registers of Naval Attache Reports, 1944-1962

Entry UD-12D 5, Series: Information Reports [U.S. Naval Attache IRs], 1951-1960

Entry UD-12D 6, Series: Information Reports [U.S. Naval Attache IRs], 1949-1960

Entry UD-12D 7, Series: Information Reports  [U.S. Naval Attaché Information Reports (IR)], 1961-1963

Entry UD-06W 20, Series: Information Reports and Requisitions [Office of Naval Intelligence Division, Naval Attaché], 1955-1956

Entry NM-63 98, Series: Intelligence Division Naval Attache Reports, 1886-1939

Entry NM-63 98-A, Series: Specially Protected Artifacts - Removed from Naval Attache Reports, 1886-1939 (See Entry NM-63 98)

Entry A1 96-B, Series: Register of Naval Attache Reports, 1909-1946

Entry A1 97-A, Series: List of Books and Pamphlets Among the Naval Attache Reports, 1900-1945

Entry NM-63 74, Series: Chronological Index To Letters To Naval Attaches, 1906-1918 (This Entry serves as an index to parts of Entry NM-63 76 & Entry NM-63 78 that relate to Naval Attaches.)

Entry NM-63 86, Series: Instructional Material Sent To Intelligence Officers And Naval Attaches, 1916-1933 

Entry NM-63 89, Series: Index To Letters Received From Naval Attaches, 1891-1898 (This Entry serves as a subject index to part of Entry NM-63 90 listed below.)

Entry NM-63 90, Series: Naval Attaches Letters, 1882 - 1900

Entry NM-63 95, Series: Record Of Correspondence From Naval Attaches, 1901-1929

Entry NM-63 97, Series: Index To Intelligence Registers, 1886-1922 (The Entry serves as an index to the list of reports of Naval Attaches in Entry NM-63 98 listed below.)

Entry NM-63 100, Series: Cable Correspondence With U.S. Naval Attaches During The Spanish - American War, January 20, 1898 - November 1, 1900

Entry NM-63 101, Series: Letters Sent to Naval Attaches, 1899-1905 (These records are indexed by Entry NM-63 72)

Entry NM-63 103, Series: Confidential Dispatches Received From Naval Attaches And Others, 1918

Entry NM-63 168, Series: Confidential Military Attache Reports From Paris & Rome, July 1937-January 1938

Entry NM-63 189, Series: Letters Sent By Naval Attaches, 1885-1905

Entry NM-63 190, Series: Secret-Confidential Files Of The U.S. Naval Attache, Rio De Janeiro, Brazil, 1919-1929 

Entry NM-63 190-A, Series: Records Of The U.S. Naval Attache, Rio De Janeiro, Brazil, 1919-1929

Entry NM-63 191, Series: General Files Of The U.S. Naval Attache, Havana, Cuba, 1917-1919 

Entry NM-63 192, Series: General Files Of The U.S. Naval Attache, Tegucigalpa, Honduras, 1929-1933

Entry NM-63 193, Series: Records Of The U.S. Naval Attache, The Hague, Netherlands, 1920-1933

Entry NM-63 195, Series: General Files Of The U.S. Naval Attache, Moscow, Russia, 1934-1935 

Entry NM-63 201, Series: Classified Records Of The U.S. Scientific Attache, London, 1917-1919

Entry NM-63 202, Series: Classified Records Of The U.S. Scientific Attache, London, Classified Miscellaneous Records, 1917-1919 

Entry UD 113, Series: Subject Classification Numerical Index To Naval Attache Reports, 1909-1946 (This index applies to Entry A1 98-A, Entry A1 98-B, and Entry NM-63 98.)

Entry UD 115, Series: Index To Registers Of Naval Attache Reports, 1946 (This Entry serves as an index to records in Entry NM-63 98.)