I've had a problem with people booking my unit, thinking I'm in Vineland, New Jersey instead of Vineland, Ontario: maybe it's an Ontario thing :-). The Vineland in NJ is close to Philadelphia, so people think they've found a cheap place to stay while visiting the city.
If people send a booking request and it seems like they might be booking the wrong location based on what they say, I mention the location to confirm that they're in the right spot. A couple of people have cancelled because they have instant booked, then figured out their mistake.
You can do what others suggest and include it prominently in your listing, but it's featured prominently in my listing as well and people still make the mistake. You can't force people to read, unfortunately!