Whoops, found the character limit:

This is tagged with the “name” “Citadel Hill” and the "official_name" "Halifax Citadel National Historic Site"


3. The administrative boundary. This is the same area as area 2, but is used for aspects of OSM mapping that I'm not familiar with. This is tagged with the "name" "Halifax Citadel National Historic Site"


The OSM convention is the use the most commonly used local name for the "name" tag and then to record the official name with the "official_name" tag. "name" is the default name tag and is generally displayed prominently by most renders. (The example in the wiki is the country of France: name=France, official_name=French Republic)

From a practical standpoint, most map apps and websites, even if they do not display the official name, will allow users to search for it. So, most people using an OSM based app to navigate to the historic site should be easily able to find it based on the information on the Parks Canada website.

Here are the relevant links if you would like to find out more:
- Wiki entry for the name tags: https://wiki.openstreetmap.org/wiki/Key:name
- The fort feature: https://www.openstreetmap.org/way/1112256004
- The archeological site feature: https://www.openstreetmap.org/way/4138857
- The administrative boundary feature: https://www.openstreetmap.org/relation/9435730