Interestingly enough zip codes don't cover the entire US. Not even the entire continental US. Lat/Long 40, -110 (in NE Utah) is a good test case to make sure yo

Interestingly enough zip codes don't cover the entire US. Not even the entire continental US. Lat/Long 40, -110 (in NE Utah) is a good test case to make sure your code handles that circumstance.