No. A city garrison will defend structures in the city, though. The
difference is that the normal garrison has a DEFEND faction (which
doesn't include any structures, no matter who owns them) while the
city garrison is doing DEFEND ALL.
> Or do/can you issue a defend order for a structure?
Yes.
> The rules say defends can be issued for units and factions. Can I
> issue a defend for the mine no matter who is in it or do I have to
> make sure all owners are on my list. Gets a bit difficult for inns
> that I want to be open to all comers.
You can issue a defend for anything, actually. This is a bug in the
rules.
-- O