: The standardized ICAO codes for global locations.
Do not confuse the two. Flight plans require both: a location indicator (Doc 7910) for departure/arrival and an aircraft operator designator (Doc 8585). doc 7910 pdf
Providing unambiguous location data during emergency coordination. Accessing the Document : The standardized ICAO codes for global locations
The primary section where indicators are listed alphabetically alongside the name of the location and the associated Flight Information Region (FIR). Alphabetical List of Locations: When manual entry is required, dispatchers refer to
Modern flight planning software (e.g., ForeFlight, Lido, Jeppesen) pulls data from an internal database that should be synchronized with DOC 7910. When manual entry is required, dispatchers refer to the PDF to verify the four-letter code for en-route alternate airports.
However, for general aviation, small operators, and individual pilots, the PDF will remain the primary reference for the foreseeable future. It requires no subscriptions beyond the initial purchase, works offline, and is universally readable.