In Rosaria's royal capital, Rosalith, the castle gates were well-guarded by soldiers, but it wasn't walled off from the rest of the city.
The wide training grounds of the west wing stretched all the way out to the suburbs and the large garden on the east wing side was open to the public.
Ordinary people were checked by guards when they entered the gardens, but as long as they meant no harm, they were even allowed to pass through to visit the temple deeper inside.
Beyond that, the facilities and towers of the Central Magic Association could be freely accessed from public roads.
Of course, not many citizens wanted to go near them due to how creepy the place felt—but that was a separate issue.
