USPS Postal Zones are how the Postal Service determines the distance between a origin and destination address. These zones range from 1-9. Zone 1 is a local shipment and Zone 9 is the furthest possible distance for a domestic shipment.
When making an automation rule based on destination address, instead of using the city name or postal code, it is far more efficient to use the destination address's postal zone. Here is an example of how that would look:
If you would like to get the best understanding of which postal codes are in which Zone, the USPS has a great tool to show the zone relationship between a postal code and all others based on their first three digits. For more info, click here.
To view these zones on an order on the orders page, select Zones from the Columns dropdown in the upper righthand side of the Orders Page.
You will then be able to view the zones on the orders page.