HoldOn: “The zip code 07675 covers three different towns in NJ: Westwood, River Vale and Old Tappan. So there’s not always a 1:1 mapping between zip and city/town. More info is required…”

Well, so why not take the ZIP code alone, and then present a menu of options only when the ZIP code actually does map to more than one city name? The existence of ambiguous cases isn’t a good reason to require unneeded input in the unambiguous cases.