Key:official_name:en-US

This key indicates the official name of a feature in the English language according to authorities in the United States, in the rare event of a discrepancy or dispute between the U.S. and another country on a feature that is not wholly located within the U.S. This key is only necessary if the discrepancy specifically pertains to the name in English and there is additionally a discrepancy between official and common usage.

The canonical example is the Gulf of Mexico. The position of the U.S. federal government differs from both common usage within the U.S. and the international consensus maintained by the International Hydrographic Organization in Limits of Oceans and Seas.

This key does not override name:en=* or name:en-US=*. Few if any renderers consume official_name=* or any of its subkeys; in practice, the purpose of this key is for geocoders to find the feature when a user searches for the official name.

In some other rare cases, further qualification is necessary at the state level due to federalism. Per BCP 47, RFC 6067, and UTS #35, we indicate each state's position using official_name:en-u-sd-usxy=*, where xy is the state's ISO 3166-2:US code (in other words, the USPS state abbreviation). For example, the federal government officially recognizes the Sea of Japan by that name, but an official_name:en-u-sd-usva=* tag indicates that the Virginia state government legally requires the use of both that name and East Sea in tandem. Contrast this situation with this lake straddling the North Carolina–Virginia border, which has differing name:en-u-sd-usnc=* and name:en-u-sd-usva=* because the states' positions match common usage within those states and signs on the ground.