List of ZIP Codes for Mountain Time: States, MST/MDT & Lookup
If you are looking for Mountain ZIP codes, this guide shows how ZIP codes map to the Mountain Time Zone time zone, which states and regions are represented, how standard time and daylight time work, and how to look up an individual ZIP code without relying on a state-level assumption. ToolTrio uses ZIP-level records because a state can cross a time-zone boundary.
Quick Answer
Mountain (MT) is represented by the standard/daylight pair MST / MDT. The UTC offsets are UTC−7 / UTC−6 when daylight saving time is observed. The U.S. Department of Transportation oversees federal time-zone boundaries, while NIST explains the standard and daylight designations.
For a ZIP-level answer, use the ZIP Code Time Zone Lookup rather than assuming that every ZIP in a state has the same time zone.
Mountain ZIP codes at a glance
The examples below are drawn from ToolTrio’s bundled ZIP dataset for orientation. They are not presented as an official USPS directory or as a complete 2026 list. For an exact ZIP, use the ZIP-level lookup tool.
States and regions represented
The table below gives representative ZIP examples from ToolTrio’s bundled dataset. It is a reference table, not a claim that every ZIP in a listed state uses the same time zone. Split states are exactly why ZIP-level lookup matters.
| State / area | Representative ZIP examples |
|---|---|
| Colorado | 80001 (Arvada), 80002 (Arvada), 80003 (Arvada), 80004 (Arvada) |
| Arizona | 85001 (Phoenix), 85002 (Phoenix), 85003 (Phoenix), 85004 (Phoenix) |
| New Mexico | 87001 (Algodones), 87002 (Belen), 87004 (Bernalillo), 87005 (Bluewater) |
| Montana | 59001 (Absarokee), 59002 (Acton), 59003 (Ashland), 59004 (Ashland) |
| Utah | 84001 (Altamont), 84002 (Altonah), 84003 (American Fork), 84004 (Alpine) |
| Idaho | 83201 (Pocatello), 83202 (Pocatello), 83203 (Fort Hall), 83204 (Pocatello) |
| Wyoming | 82001 (Cheyenne), 82002 (Cheyenne), 82003 (Cheyenne), 82005 (Fe Warren Afb) |
| Texas | 79821 (Anthony), 79835 (Canutillo), 79836 (Clint), 79837 (Dell City) |
| South Dakota | 57521 (Belvidere), 57537 (Hayes), 57543 (Kadoka), 57547 (Long Valley) |
| Nebraska | 69021 (Benkelman), 69023 (Champion), 69027 (Enders), 69030 (Haigler) |
| North Dakota | 58520 (Almont), 58523 (Beulah), 58528 (Cannon Ball), 58529 (Carson) |
| Kansas | 67733 (Edson), 67735 (Goodland), 67741 (Kanorado), 67758 (Sharon Springs) |
List of ZIP Codes for Mountain Time
If you searched for list of ZIP codes for Mountain Time, this is the practical reference section of the guide. The list below gives ZIP codes currently classified by ToolTrio's bundled dataset under the Mountain-time IANA families America/Denver, America/Boise, or America/Phoenix. It is grouped by state so you can scan the list quickly instead of working through one giant undifferentiated ZIP directory.
The current ToolTrio dataset contains 3,163 ZIP records in these three Mountain-time IANA families. That is a ToolTrio dataset count, not an official USPS ZIP-code total. For an individual ZIP, use the ZIP-level lookup because state boundaries and time-zone boundaries do not always line up.
| State / area | ZIP codes in the Mountain-time dataset |
|---|---|
| Arizona | 85001, 85002, 85003, 85004, 85005, 85006, 85007, 85008, 85009, 85010, 85011, 85012, 85013, 85014, 85015 |
| Colorado | 80001, 80002, 80003, 80004, 80005, 80006, 80007, 80010, 80011, 80012, 80013, 80014, 80015, 80016, 80017 |
| Idaho | 83201, 83202, 83203, 83204, 83205, 83206, 83209, 83210, 83211, 83212, 83213, 83214, 83215, 83217, 83218 |
| Kansas | 67733, 67735, 67741, 67758, 67761, 67762, 67836, 67857, 67878, 67879 |
| Montana | 59001, 59002, 59003, 59004, 59006, 59007, 59008, 59010, 59011, 59012, 59013, 59014, 59015, 59016, 59018 |
| Nebraska | 69021, 69023, 69027, 69030, 69033, 69037, 69041, 69045, 69121, 69122, 69125, 69127, 69128, 69129, 69131 |
| New Mexico | 87001, 87002, 87004, 87005, 87006, 87007, 87008, 87009, 87010, 87011, 87012, 87013, 87014, 87015, 87016 |
| North Dakota | 58520, 58523, 58528, 58529, 58533, 58535, 58538, 58541, 58545, 58554, 58562, 58563, 58564, 58566, 58568 |
| South Dakota | 57521, 57537, 57543, 57547, 57551, 57552, 57553, 57555, 57560, 57562, 57563, 57566, 57567, 57570, 57572 |
| Texas | 79821, 79835, 79836, 79837, 79838, 79839, 79849, 79851, 79853, 79901, 79902, 79903, 79904, 79905, 79906 |
| Utah | 84001, 84002, 84003, 84004, 84005, 84006, 84007, 84008, 84009, 84010, 84011, 84013, 84014, 84015, 84016 |
| Wyoming | 82001, 82002, 82003, 82005, 82006, 82007, 82008, 82009, 82010, 82050, 82051, 82052, 82053, 82054, 82055 |
How to use this Mountain Time ZIP code list
This table is useful when you need examples or want to understand which parts of a state appear in the Mountain-time dataset. It should not be treated as a permanent postal directory. ZIP assignments and supporting geographic datasets can change, and some states are split across time zones. If you have a specific ZIP such as 80202, 85001, 87102, 84101, 82001, or 79835, enter that ZIP into ZIP Code Time Zone Lookup to get the site's current record.
For developers building a ZIP-to-time-zone workflow, keep the five-digit ZIP as the source value and store the resolved IANA identifier separately. That approach is more reliable than storing only MST or MDT, because Arizona and other locations do not follow the same seasonal rule.
Looking for the complete list of ZIP codes for Mountain Time? Use Same Time Zone ZIPs to explore ZIPs that share a time-zone classification, or use the direct lookup for a particular ZIP.
ZIP code vs. state: why the distinction matters
A ZIP code is not a time-zone code. ZIP Codes are created for postal delivery, while time-zone boundaries are legal geographic boundaries. A state may contain ZIP records in more than one time zone, particularly near state borders. That means a rule such as “all ZIP codes in this state use Mountain” can be wrong even when the state itself is strongly associated with Mountain.
The safer workflow is ZIP → time-zone record → local time. ToolTrio follows that model in its lookup tools.
MST / MDT: what the abbreviations mean
The generic label MT is useful when you mean local time in the zone without committing to whether daylight saving time is currently active. During standard time the abbreviation is the first half of the pair; during daylight time it is the second. NIST lists the U.S. standard/daylight pairs and their UTC offsets.
Do not treat an abbreviation such as MST as a permanent year-round label for every location. Daylight-saving rules can change the displayed abbreviation and UTC offset. Arizona is an important example elsewhere in the Mountain region because most of the state does not observe DST.
How to find the time zone for a ZIP code
- Enter the five-digit ZIP into ZIP Code Time Zone Lookup.
- Check the returned IANA time-zone identifier and human-readable zone.
- If you need a map view, open ZIP Code Time Zone Map.
- For a broader list, use Same Time Zone ZIPs when you want ZIPs sharing the same zone.
- If the ZIP is being used for an address workflow, separately verify the postal address with USPS Address Format.
This separation matters because a postal format question and a time-zone question are different tasks.
Practical use cases for Mountain ZIP codes
Scheduling and customer support: If a customer record contains a ZIP but not a reliable time zone, resolving the ZIP before scheduling a call helps avoid sending an appointment at the wrong local hour. The same approach works for support queues, appointment reminders and notification systems.
Marketing and audience segmentation: ZIP-level time-zone data can be useful for sending campaigns during a preferred local-time window. Keep the time zone as a derived attribute rather than replacing the original ZIP, so the record can be refreshed if the underlying geographic data changes.
Operations and logistics: Dispatch dashboards, delivery estimates and field-service applications often need local time at a location. A ZIP-level time-zone lookup can provide a practical first classification, while address-level routing should still use the more precise data required by the operation.
Software development: Store ZIP codes as strings and preserve leading zeroes. Store the resolved IANA identifier separately from the display abbreviation. This lets the application convert timestamps correctly when daylight-saving rules change instead of relying on a fixed UTC offset.
How to choose the right source
Use DOT when the question is about the legal U.S. time-zone boundary. Use NIST when you need a clear explanation of standard time, daylight time and UTC offsets. Use a ZIP-level dataset when the question is specifically “what time zone is this ZIP associated with?” These sources answer related but different questions.
ToolTrio combines those layers in the user experience: the guide explains the rule, the ZIP dataset supplies the ZIP-level association, and the lookup tool gives the result for the user's input. That separation makes the page more useful than a generic list of state names and also makes it easier to audit a result.
Common search variations this guide answers
People use several natural phrases for the same underlying task: ZIP codes in Mountain, Mountain ZIP codes, ZIP codes for Mountain time, Mountain time zone ZIP code list, ZIP codes in Mountain time zone, and what ZIP codes are Mountain. These phrases describe the same general information need, but the correct answer should remain ZIP-level rather than producing a different page for every wording variation.
Mountain ZIP code examples
A few examples from the bundled ToolTrio ZIP dataset are shown below. These examples are for orientation; they are not intended to be a substitute for checking the exact ZIP requested by a user.
| ZIP Code | Primary city in dataset | State | Zone |
|---|---|---|---|
| 80001 | Arvada | Colorado | MT |
| 80002 | Arvada | Colorado | MT |
| 85001 | Phoenix | Arizona | MT |
| 85002 | Phoenix | Arizona | MT |
| 87001 | Algodones | New Mexico | MT |
| 87002 | Belen | New Mexico | MT |
| 59001 | Absarokee | Montana | MT |
| 59002 | Acton | Montana | MT |
| 84001 | Altamont | Utah | MT |
| 84002 | Altonah | Utah | MT |
| 83201 | Pocatello | Idaho | MT |
| 83202 | Pocatello | Idaho | MT |
| 82001 | Cheyenne | Wyoming | MT |
| 82002 | Cheyenne | Wyoming | MT |
| 79821 | Anthony | Texas | MT |
| 79835 | Canutillo | Texas | MT |
Edge cases to understand before publishing a ZIP list
Split states
Several U.S. states contain more than one time zone. A state-level list can therefore hide the exact boundary that matters to a user. The DOT maintains official time-zone boundaries, and its geospatial time-zone layer is the appropriate reference for boundary questions.
Arizona and daylight saving time
Arizona is a frequent source of confusion in Mountain Time searches. Most of Arizona remains on Mountain Standard Time year-round rather than switching between MST and MDT like most Mountain-zone states. The Navajo Nation is a notable exception and observes daylight saving time. If you need a current local-time answer, use the ZIP-level record instead of applying a blanket Arizona rule.
ZIP Codes are not Census ZCTAs
A ZIP Code and a Census ZCTA are related but not interchangeable. A ZCTA is a statistical representation created by the Census Bureau; it should not be presented as though it were the USPS ZIP Code itself. This distinction matters when a page combines postal, demographic, mapping, or population information.
Postal changes and data freshness
ZIP assignments, city names, delivery areas and supporting datasets can change. For a static article, show a refresh date and avoid implying that a sample table is a permanent official directory. For an individual lookup, use the live ToolTrio record and verify high-impact postal decisions against the appropriate primary source.
When should you use a ZIP time-zone lookup?
A ZIP-level time-zone lookup is useful for scheduling calls, calculating business hours, routing notifications, estimating local event times, building customer-service workflows, segmenting marketing lists, and displaying local time in a web application. It is especially valuable when the input is a ZIP code and the application needs an unambiguous time-zone identifier rather than a state name.
For developers, storing the IANA identifier is generally more useful than storing only “Mountain.” The IANA value carries the location rule set that software can use for UTC conversions and daylight-saving transitions. A display label can then be generated for the user.
Common Mountain Time ZIP-code questions
Searches such as ZIP codes for Mountain Time, ZIP codes in Mountain Time, what ZIP codes are in Mountain Time, Mountain time zone ZIP code list, MST ZIP codes, MDT ZIP codes, and find ZIP codes in Mountain Time describe slightly different wording for the same lookup task. The exact ZIP matters because Mountain Time coverage crosses state boundaries and Arizona has a different daylight-saving pattern from most of the Mountain region.
Frequently asked questions
What ZIP codes are in Mountain time?
There are many ZIP Codes associated with Mountain Time, but the exact set depends on the ZIP-level dataset being used. Because some states are split across time zones, determine the zone from the individual ZIP rather than from the state alone.
Is Mountain the same as MST?
Not exactly. Mountain is the generic time-zone name. The standard and daylight abbreviations identify which clock rule is active at a given time of year.
Can I get a complete ZIP list?
Yes, but a complete directory is best treated as data rather than a hand-written article. Use the ToolTrio ZIP time-zone tools to search a specific ZIP or explore ZIPs sharing a time zone. The tables in this guide provide a readable reference while the tool handles individual lookups.
Does every ZIP in a Mountain-associated state use Mountain?
No. Some states cross time-zone boundaries. Check the ZIP itself.
Can I use a ZIP code to calculate local time?
Yes. Resolve the ZIP to its time-zone identifier first, then convert the desired timestamp using a time-zone-aware library. Avoid simply subtracting a fixed number of hours because daylight-saving rules can change the offset.
Where can I verify official time-zone boundaries?
The U.S. Department of Transportation oversees U.S. time zones and publishes the official regulatory framework and geospatial resources. NIST also documents U.S. standard and daylight time designations.
2026 data and accuracy note
Reviewed October 3, 2026. The time-zone rules in this guide are checked against the current IANA Time Zone Database release 2026e, released September 29, 2026, plus the U.S. Department of Transportation’s official time-zone framework and NIST’s U.S. time-zone offset table. The ZIP examples are read from ToolTrio’s local static ZIP dataset; this article does not call an API at page load. Because there is no single USPS table that publishes a ZIP-to-time-zone directory, ToolTrio does not label its local ZIP examples as an official USPS time-zone list.
Sources and methodology
- U.S. Department of Transportation: Uniform Time — official federal overview of U.S. time zones and DOT responsibility.
- U.S. Department of Transportation / Data.gov: Time Zones dataset — geospatial representation of U.S. time-zone boundaries.
- NIST: Local Time FAQs — standard/daylight abbreviations and UTC offsets.
- ToolTrio dataset: bundled ZIP records used by this site, grouped by IANA time-zone identifier. Dataset counts in this guide are a ToolTrio snapshot, not an official USPS count.
Practical takeaway
If someone searches for Mountain ZIP codes, give them both things they actually need: a readable reference and a precise lookup. The reference explains the geography; the lookup resolves the individual ZIP. That combination is more useful than a giant static keyword list and is easier to keep accurate as postal and geographic data changes.