| Appendix E: Cross-Reference List of Hydrographic Data Codes |
IHO 23-4th: Limits of Oceans and Seas, Special Publication 23, Draft 4th Edition 1986, published by the International Hydrographic Bureau of the International Hydrographic Organization IHO 23-3rd: Limits of Oceans and Seas, Special Publication 23, 3rd Edition 1953, published by the International Hydrographic Organization ACIC M 49-1: Chart of Limits of Seas and Oceans, revised January 1958, published by the Aeronautical Chart and Information Center (ACIC), United States Air Force; note - ACIC is now part of the National Imagery and Mapping Agency (NIMA) DIAM 65-18: Geopolitical Data Elements and Related Features, Data Standard No. 4, Defense Intelligence Agency Manual 65-18, December 1994, published by the Defense Intelligence Agency The US Government has not yet adopted a standard for hydrographic codes similar to the Federal Information Processing Standards (FIPS) 10-4 country codes. The names and limits of the following oceans and seas are not always directly comparable because of differences in the customers, needs, and requirements of the individual organizations. Even the number of principal water bodies varies from organization to organization. Factbook users, for example, find the Atlantic Ocean and Pacific Ocean entries useful, but none of the following standards include those oceans in their entirety. Nor is there any provision for combining codes or overcodes to aggregate water bodies. The recently delimited Southern Ocean is not included.

Principal Oceans and Seas of the World With Hydrographic Codes by Institution
| IHO 23-4th | IHO 23-3rd* | ACIC M 49-1 | DIAM 65-18 |
Arctic Ocean | 9 | 17 | A | 5A |
Atlantic Ocean | - | - | - | - |
North Atlantic Ocean | 1 | 23 | B | 1A |
South Atlantic Ocean | 4 | 32 | C | 2A |
Baltic Sea | 2 | 1 | B26 | 7B |
Indian Ocean | 5 | 45 | F | 6A |
Mediterranean Sea | 3.1 | 28 | B11 | - |
Eastern Mediterranean | 3.1.2 | 28 B | - | 8E |
Western Mediterranean | 3.1.1 | 28 A | - | 8W |
Pacific Ocean | - | - | - | - |
North Pacific Ocean | 7 | 57 | D | 3A |
South Pacific Ocean | 8 | 61 | E | 4A |
South China and Eastern Archipelagic Seas | 6 | 49, 48 | D18 plus others | 3U plus others |
*The letters after the numbers are subdivisions, not footnotes.