You can use a square (x, y and x1, y1) which is (of course) not that accurate. In one of my projects I use Google's geocode function. Input is lan/lon and you get the full address of that location. Here you can check if it's New York City or at least New York state or whatever you need.
It's just a simple api call with OkHttpUtils. You get a JSON result which you can parse (like zip / name of the city, etc.)
Sub GetAddress (lat As Float, lon As Float)
Dim GetAddressJob As HttpJob
GetAddressJob.Initialize("GetAddress", Me)
GetAddressJob.Download2("https://maps.googleapis.com/maps/api/geocode/json", _
Array As String("latlng", lat & "," & lon))
End Sub