A small advice from a native German: watch the genders of the words. Cities are normally no problem but larger regions have often names with articles. Examples:
"The Westmarch" - "Die Westmark" (feminin)
"The Swamp of terror" - "Der Sumpf des Schreckens" (masculin)
"The Realm of XY" - "Das Reich von XY" (neutral)
The simplest solution is to go with plural, then "die" is always correct (at least in Nominativ).
 TBF (further down) is right. I was asking myself why my examples sounded so awkward.