I am testing a solution for a tax calculation system, and some states have zip code ranges with specific taxes, so I need to know if there are zip codes that correspond to different locations. One part of the system uses different combinations of city/zip to find the county, because some locales have taxes that vary by county.
Are there zip codes that correspond to more than one location but are separate from each other, possibly in different states or counties?
I know that a zip code can span cities and/or states but I want to know if there are zip codes that are completely autonomous of one another but share the same code.
Is there a way that I can find up-to-date information about this?