Location ending in “S” and adding a singular or Plural?

Location ending in “S” and adding a singular or Plural?

I’m creating a youtube channel and I need a username. I live in the “Twin Cities” area in Minneapolis Minnesota, so I was going to name my Channel either “Twin Cities Pranks” or “Twin City Pranks”. I need to know which one is grammatically correct? I’ve been told to use Plural and I’ve also been told it was Subjective… Please help!!