When filling in a U.S. tax-free state address, the step that most often gets stuck is not choosing the state, but finding "the correct ZIP code corresponding to the city." The same city may have multiple ZIP codes, and the ZIP code prefixes of different cities may also look similar. Manually piecing them together is error-prone, and once the state, city, and ZIP code do not match, the address may be judged invalid. This article organizes the correspondence between major cities and ZIP codes in the 5 tax-free states into a quick reference table you can directly compare against. If you do not want to check item by item, you can directly use the U.S. Tax-Free State Address Generator to generate a complete, already-matched address.

1. Delaware's Three Counties and ZIP Codes

Delaware is small in area and has only three counties: New Castle County, Kent County, and Sussex County. Major cities are concentrated in New Castle County and Kent County.

  • Wilmington: The largest city in Delaware, located in New Castle County. ZIP codes are mainly 198xx, with common ones including 19801 (downtown), 19805, 19808, etc.
  • Newark: Home to the University of Delaware, also in New Castle County. Common ZIP codes include 19711, 19702, 19713, etc.
  • Dover: The state capital, located in Kent County. Representative ZIP codes are 19901 and 19904.

Delaware ZIP codes as a whole fall within the 197–199 range, and the major cities in the three counties each have fixed number segments. When you need to generate a Delaware address, you can use the Delaware Address Generator.

2. Oregon's 97x ZIP Code Segment

Oregon ZIP codes start with 97, covering the entire 970–979 range. The major cities in the state are distributed as follows:

  • Portland: The largest city in Oregon, with ZIP codes concentrated in the 972xx segment. Common ones include 97201, 97202, 97214, 97217, etc.
  • Salem: The state capital, with ZIP codes mainly 97301, 97302, 97304, 97305.
  • Eugene: A university city, with common ZIP codes including 97401, 97402, 97403, 97405.
  • Beaverton: A city in the Portland metropolitan area, with ZIP codes such as 97005, 97006, 97007, 97008.

Oregon's ZIP code pattern is clear: 972 corresponds to Portland, 973 corresponds to Salem and surrounding areas, and 974 corresponds to the Eugene direction. When you need an Oregon address, you can use the Oregon Address Generator .

3. Major Cities in Alaska

Alaska's ZIP code range is 995–999, a very wide span, but commonly used cities are concentrated in a few number segments.

  • Anchorage: The largest city, with ZIP codes mainly 995xx, such as 99501, 99503, 99519, etc. Anchorage does not levy a general local sales tax, making it a relatively safe choice for Alaska addresses.
  • Fairbanks: The main inland city, with common ZIP codes including 99701, 99707, 99775, etc.
  • Juneau: The state capital, with ZIP codes such as 99801. Note that Juneau levies a local sales tax, so pay attention to city differences when choosing an address.

The key to an Alaska address is not the "state" but the "city." Even when choosing Alaska, the actual tax burden in Anchorage and Juneau may differ. When generating, it is recommended to prioritize Anchorage; you can use the Alaska Address Generator .

4. City Distribution in Montana

Montana's ZIP code range is 590–599, and major cities are distributed in the south-central and western parts.

  • Billings: The largest city in Montana, with ZIP codes concentrated in the 591xx segment, such as 59101, 59102, 59105, 59106.
  • Helena: The state capital, with common ZIP codes 59601, 59602, 59620.
  • Missoula: A western city, with ZIP codes such as 59801, 59804.
  • Bozeman: A southwestern city, with ZIP codes such as 59715. Note that Bozeman is a designated resort community, and some purchases may involve a resort tax.

To generate a Montana address, you can use the Montana Address Generator .

5. New Hampshire ZIP Code Segment

New Hampshire ZIP codes start with 0, with a range of 030–038. The leading 0 cannot be omitted when filling in.

  • Manchester: The largest city, with ZIP codes starting with 031, common ones including 03101, 03103, 03109.
  • Nashua: A southern city, with ZIP codes such as 03060, 03064.
  • Concord: The state capital, with ZIP codes starting with 033, such as 03301, 03302.

A common mistake with New Hampshire addresses is "swallowing the leading 0," writing 03101 as 3101. When generating addresses, you can use the New Hampshire Address Generator to avoid such formatting issues.

6. How to Check Whether a City and ZIP Code Match

After obtaining a city and a ZIP code, you can use the following steps to quickly verify them:

  • Check whether the first three digits of the ZIP code fall within that state's range. Delaware 197–199, Oregon 970–979, Alaska 995–999, Montana 590–599, New Hampshire 030–038. If the ZIP code prefix is not within this range, there is already a problem with the city-state match.
  • Compare against the city ZIP code table in this article. The same city is usually concentrated in a fixed number segment. For example, Portland is in 972xx and Manchester is in 031xx. If there is an obvious deviation, be cautious.
  • Use the official USPS tool for final confirmation. USPS provides a Zip Code Lookup service. Enter the city and state to query the corresponding ZIP code, which is the final basis.

The easiest way is still to generate a complete address that has already been verified. The U.S. Tax-Free State Address Generator covers 5 states and generates the state, city, and ZIP code all at once, with no manual comparison needed.

7. Conclusion

The relationship between cities and ZIP codes in the five tax-free states can be summarized as: for Delaware, look at the three counties (Wilmington 198xx, Newark 197xx, Dover 199xx); for Oregon, look at the three segments 972/973/974; for Alaska, prioritize Anchorage 995xx; for Montana, Billings 591xx; for New Hampshire, pay attention to the leading 0. Remembering these number segment patterns gives you an anchor for quick judgment when filling in addresses manually.