The 5 U.S. tax-free states are geographically scattered: some are in the northeast corner, some in the northwest, some across the border from Canada, and one is a small state on the East Coast. This scattered geographic layout directly determines that their ZIP code ranges each occupy a separate segment and do not overlap. Understanding "which state is where, which number range its ZIP codes fall into, and which ZIP codes correspond to major cities" is the foundation for quickly judging whether a tax-free state address is real and valid. If you need to generate addresses directly, you can visit the U.S. Tax-Free State Address Generator.

1. Geographic Locations of the 5 States

First, place the five states on a map to build a sense of space.

  • Delaware (DE): Located in the mid-Atlantic region of the U.S. East Coast, bordering the Atlantic Ocean, it is very small and is the second-smallest state in the U.S. It sits between Maryland and Pennsylvania, not far from Philadelphia, Baltimore, and Washington.
  • New Hampshire (NH): Located in the New England region of the northeastern U.S., bordering Canada to the north and the Atlantic Ocean to the east, it is known as the "Granite State" for its abundant granite.
  • Montana (MT): Located in the northwestern U.S., it ranks fourth in area nationwide but has a very low population density. It borders Canada to the north, and its economy is mainly based on agriculture and animal husbandry, mining, and logging.
  • Oregon (OR): Located on the U.S. Pacific coast, bordering Washington State to the north and California to the south, with a mild climate.
  • Alaska (AK): Located at the northwestern tip of the North American continent, bordering Canada to the east and facing the Arctic Ocean, Bering Sea, and North Pacific Ocean on its other three sides, it is the largest state in the U.S. by area.

These five states are distributed from east to west and from south to north, but their ZIP code ranges are not simply arranged in geographic order. The first digit of a ZIP code reflects the major regional division of the United States, so they need to be looked at separately.

2. Which Ranges Each State's ZIP Code Segment Falls Into

The first digit of a U.S. ZIP code ranges from 0 to 9, roughly increasing from east to west. The ZIP code ranges of the 5 tax-free states are as follows, based on state-level ZIP code ranges listed by the U.S. Internal Revenue Service (IRS) and military postal standards:

  • New Hampshire (NH): 030–038. Starts with 0, belonging to the eastern ZIP code region.
  • Delaware (DE): 197–199. Starts with 1, adjacent to Pennsylvania's ZIP code segment (150–196).
  • Montana (MT): 590–599. Starts with 5, belonging to the north-central western ZIP code segment.
  • Oregon (OR): 970–979. Starts with 9, belonging to the western ZIP code region.
  • Alaska (AK): 995–999. Also starts with 9, but the range comes after Oregon and is one of the highest-numbered ZIP code ranges in the entire U.S.

Numerically, New Hampshire and Delaware are in the low-numbered eastern segment, Montana is in the middle, and Oregon and Alaska are in the high-numbered western segment. These five ranges have no overlap, and each state's ZIP codes fall within its own exclusive number range.

3. Major Cities Within Each State

Each tax-free state has several cities that appear frequently in actual address filling. Knowing these cities is more practical than memorizing the entire state's ZIP code range.

  • Delaware: Wilmington is the largest city and the place where commercial addresses are most concentrated; Dover is the state capital; Newark is common because of the University of Delaware.
  • Oregon: Portland is the largest city and the most commonly used city for forwarding and receiving addresses; Salem is the state capital; Eugene and Beaverton are also common cities.
  • Montana: Billings is the largest city; Helena is the state capital; Missoula and Bozeman are important cities in the west.
  • New Hampshire: Manchester is the largest city; Concord is the state capital; Nashua is also a populous city in the south.
  • Alaska: Anchorage is the largest city and the most commonly selected city when filling in addresses; Fairbanks is the main inland city; Juneau is the state capital.

If you need to generate or verify addresses, prioritize these major cities. The correspondence between ZIP codes and cities is clearer and more easily recognized correctly by shopping websites and payment systems.

4. Correspondence Between Cities and ZIP Codes

Cities and ZIP codes are not one-to-one. A large city may have multiple ZIP codes, a small town may have only one ZIP code, or may even share the ZIP code of a neighboring city. Below are the typical ZIP code segments corresponding to major cities in each state:

  • Wilmington (DE): 19801–19899 range.
  • Dover (DE): 19901–19906.
  • Newark (DE): around 19711–19726.
  • Portland (OR): mainly 972xx, such as 97201.
  • Billings (MT): 59101–59117.
  • Helena (MT): around 59601–59626.
  • Missoula (MT): 59801–59812.
  • Anchorage (AK): mainly 995xx, such as 99501, 99599.
  • Fairbanks (AK): commonly 99701, etc.

When you need a specific Delaware address, you can use the Delaware Address Generator; for Oregon addresses, use the Oregon Address Generator ; for Alaska addresses, use the Alaska Address Generator .

The address generation entries for Montana and New Hampshire are respectively Montana Address Generator and New Hampshire Address Generator.

5. ZIP Codes Do Not Repeat Across States

This is a common question: will different states use the same ZIP code?

From the design of state-level ZIP code ranges, the ZIP code segments of the 5 tax-free states do not overlap at all. New Hampshire is in 030–038, Delaware in 197–199, Montana in 590–599, Oregon in 970–979, and Alaska in 995–999. The first three digits of each 5-digit ZIP code already define the state to which it belongs, and there is no situation where one ZIP code belongs to two tax-free states at the same time.

However, one technical detail needs attention: the essence of a ZIP code is a postal delivery route, not a strict administrative boundary. In other parts of the United States, there are indeed a very small number of ZIP codes that cross state or municipal boundaries. But for the main ZIP code ranges of these 5 tax-free states, state-level attribution is clear and stable. When filling in shopping or forwarding addresses in daily life, as long as the ZIP code falls within the above ranges, the match between state and ZIP code is correct.

So the judgment rule can be simplified into one sentence: see which tax-free state's range the first three digits of the ZIP code fall into, and choose that state. If you do not want to compare manually, simply use the U.S. Tax-Free State Address Generator to generate a complete address; the state, city, and ZIP code are already matched.

6. Conclusion

The geographic distribution of the 5 tax-free states determines their ZIP code ranges: New Hampshire and Delaware in the east occupy the low-numbered segment, Montana is in the middle, and Oregon and Alaska are in the high-numbered western segment. The correspondence between major cities and ZIP codes in each state is the core reference for address filling, and because the ZIP code ranges of the tax-free states do not overlap, the method of "determining the state by ZIP code" is sufficiently reliable.

When you need a specific address, the U.S. Tax-Free State Address Generator covers all 5 states and can generate a logically consistent complete address with one click.