There is something awry in the way Basecamp fills out the dropdown list when doing a search for a city.
For example, if you are looking for Greenville, SC and you enter Greenville, the dropdown list will contain 12 Greenvilles but not Greenville,SC.
If you type in Greenville,SC the list will be populated with a single Greenville,SC entry. So the map, CNNT2013.3, knows that Greenville,SC exists.
Is there a limit to the size of the dropdown list?
This is just an example. I've seen this behaviour on several searches.