Address Verification

State & County FIPS Codes: Meaning, Uses, and More

By 6 December 2023April 22nd, 2024No Comments
state county fips codes

State & County FIPS Codes: Meaning, Uses, and More

We all know what a county means and the first thing that comes to our mind on hearing it is that it’s a part of a country. Though this meaning is correct to a certain extent, there is far more to it.

A county is a geographical area of a country created for political, administrative, and other reasons. Usually, county governments are separate from state governments and work independently.

state county fips codes

But remember that counties are not the same as a state but rather form various small parts of a state. For example, Jackson County in the United States is just a part of Missouri, and there are 113 other counties in this state.

Today, counties are functional in 48 US states, while the other two states Louisiana and Alaska, have parishes and boroughs, respectively. They function in the same way as counties but with some minor variations.

Similarly, there are several other places that are the same as counties but go by different names. They are known as county equivalents.

So, how do you identify these counties and county equivalents? Is there a unique county identifier or code? If yes, what is a county code?

Well, the answer is that all the counties in the US have a FIPS code. FIPS codes are numeric characters used to identify counties and states in the US.

Typically, they assure smooth data exchanges across technical communities, contractors, and government agencies.

Generally speaking, FIPS codes are helpful to forecast weather, verify mailing addresses, protect data security, etc. For example, the NOAA Weather Radio uses FIPS codes to broadcast weather and upcoming hazards via the Emergency Alert System (EAS).

Still, these details raise several other questions, like how are FIPS codes made or are they the same as ZIP codes? In this blog, we will cover everything that you need to know about county FIPS codes.

So, let’s dive in!

How Were FIPS Codes Established in the US?

Confused about how county FIPS codes first came into existence? Keep reading to discover the complete process.

The National Institute of Standards and Technology (NIST) is the responsible authority who created the FIPS (Federal Information Processing Standards) codes system. First, it issued the Federal Information Processing Standard Publication 6-4 (FIPS 6-4), consisting of FIPS codes that uniquely identified counties and their equivalents in the US.

Later on, the FIPS 6-4 was withdrawn by the NIST as it was outdated. The NIST decided to replace it with the INCITS 31 – 2009 codes to identify states and counties.

Soon after that, the U.S. Census Bureau approved this replacement and also assigned new and updated codes. However, it also decided that these new codes would continue to use the FIPS name wherein FIPS stood for FIP “Series” as it officially removed the “Standard.”

From here on, FIPS codes are assigned to every county in the US. They consist of five digits and the first two digits are called the state FIPS codes. The remaining three numbers indicate the exact county code. So, for example, the FIPS code of Brown County is 39015- 39 stands for the state of Ohio, and 015 indicates the county.

It is the process of how state code and country code makes a FIPS code. So, for conducting a FIPS county lookup, the first search for the 2-digit state codes USA. Once you find the state, it gets relatively easy to search for the county.

You would also find it interesting to know that county FIPS codes are usually assigned alphabetically within every state. For example, Delaware has three counties named Kent, Sussex, and New Castle, and the state FIPS code of Delaware is 10. The FIPS codes for the three counties are assigned as:

  • Kent County – 10001
  • New Castle – 10003
  • Sussex – 10005

Here, you will notice that every county is given an odd number. The even numbers are kept unused to fit in changed or new county names without disturbing the alphabetical order of the FIPS codes.

US State FIPS Codes

As mentioned above, every US state has a 2-digit state FIPS code. These codes are assigned alphabetically and in ascending order.

Like county codes, some numbers are also missing in the state codes. The purpose of these missing numbers was to accommodate new states into the FIPS code system while maintaining the sequence.

For example, state codes 14 (for Guam), 43 (for Puerto Rico), and 52 (for the Virgin Islands) are kept unused. If these places become a US state in the future, these codes will be rightly assigned to them.

Find below a state FIPS list for all the 50 states in the US:

State/ Territory/ Outlying Area State Abbreviation State FIPS Code
Alabama AL 01
Alaska AK 02
Arizona AZ 04
Arkansas AR 05
California CA 06
Colorado CO 08
Connecticut CT 09
Delaware DE 10
District of Columbia DC 11
Florida FL 12
Georgia GA 13
Hawaii HI 15
Idaho ID 16
Illinois IL 17
Indiana IN 18
Iowa IA 19
Kansas KS 20
Kentucky KY 21
Louisiana LA 22
Maine ME 23
Maryland MD 24
Massachusetts MA 25
Michigan MI 26
Minnesota MN 27
Mississippi MS 28
Missouri MO 29
Montana MT 30
Nebraska NE 31
Nevada NV 32
New Hampshire NH 33
New Jersey NJ 34
New Mexico NM 35
New York NY 36
North Carolina NC 37
North Dakota ND 38
Ohio OH 39
Oklahoma OK 40
Oregon OR 41
Pennsylvania PA 42
Rhode Island RI 44
South Carolina SC 45
South Dakota SD 46
Tennessee TN 47
Texas TX 48
Utah UT 49
Vermont VT 50
Virginia VA 51
Washington WA 53
West Virginia WV 54
Wisconsin WI 55
Wyoming WY 56
American Samoa AS 60
Federated States of Micronesia FM 64
Guam GU 66
Johnston Atoll JA 67
Marshall Islands MH 68
Northern Mariana Islands MP 69
Palau PW 70
Midway Islands MI 71
Puerto Rico PR 72
U.S. Minor Outlying Islands UM 74
Navassa Island NI 76
Virgin Islands of the U.S. VI 78
Wake Island WI 79
Baker Island BI 81
Howland Island HI 84
Jarvis Island JI 86
Kingman Reef KR 89
Palmyra Atoll PA 95

The county FIPS codes are added ahead of these state FIPS codes to get the complete 5-digit code. Click here to get a full list of all the FIPS codes in the US.

How to Conduct FIPS Code Lookup By Address and ZIP Code

After knowing what is a FIPS code and what its uses are, you might be wondering how to find yours.

Well, there are two prime options to search for FIPS codes. Either you can conduct a FIPS code lookup by ZIP code (the difficult way) or by individual address (the smart way).

Below, we have discussed why searching for FIPS codes using ZIP codes and city names is not the best way to go. We have also covered how knowing the street address speeds up the process of finding FIPS codes.

FIPS Code Lookup By ZIP Code

Using ZIP codes to look up county codes is like finding a tiny shell in a vast ocean. It is daunting, time-consuming, and not very effective. Also, this process does not guarantee any results; you may or may not find the correct FIPS code.

The same goes for county code lookup by city names. Again, it is because a single city may have hundreds of county lines passing through it.

Besides, it is not unusual for ZIP codes, cities, and states to cross more than one county. There is no city in the US that does not have at least two county lines passing through it.

Let’s take an example of the city of Leeds, situated in Alabama. If you only think about it as a city in a state, nothing’s confusing, right? But wait until counties come in, and you have to re-think the whole geographic scenario.

Now, Leeds is the intersection point of three counties, and its ZIP code is 35094. If you enter this ZIP code in a FIPS lookup box, you are going to get three FIPS codes as a result. Therefore, in this case, it is hard to ascertain which code is the correct one.

Imagine you are an insurance agent, and your customer lives in Leeds to get a practical understanding. To make things more complicated further, imagine you don't have the customer's exact street address. But, you need to find the FIPS code to offer the right insurance plans according to the location.

So, what will you do in this situation? Of course, your first thought will be to find a county by city and state names. However, if you do that, you are going to get three results. Either your customer stays in Saint Clair County, Jefferson County, or Shelby County. Hence, you are back to square one.

However, Leeds is not the only county to face such issues. Some US cities are also split into five counties, like:

  • New York City in New York is split into five counties.
  • Aurora, Illinois, is divided into three counties.
  • Allentown, Georgia, has a population of only 158 people and is yet divided into four counties, which is pretty surprising.

In total, the US has:

  • Two cities with five counties
  • Ten cities with four counties
  • 61 cities with three counties
  • 611 cities with two counties

Hence, if you use one city name or one ZIP code and expect to find just one FIPS code, it is safe to say that it is unrealistic.

However, it is certainly possible if you want to carry out a reverse county lookup where you find a city with the help of a FIPS code.

FIPS Code Lookup By Address 

Finding FIPS codes using physical addresses is easy, fast, and efficient. Moreover, it is the best way to search for a FIPS code accurately.

Through this method, you need not guess the correct code from a long FIPS code list. Instead, you get precise results and better clarity on the county location.

Are ZIP Codes and FIPS Codes the Same Thing?

At first glance, you may think that ZIP codes and FIPS codes are the same things. But, please note that a county only has one FIPS code but can have several ZIP codes.

Orange County in California has the FIPS code “06059.” However, you will find more than 100 ZIP codes inside the county, like 92861, 92862, 92863, etc.

Let’s list down the prime differences between ZIP codes and FIPS codes.

  • ZIP stands for Zone Improvement Plan and was introduced to increase mailing efficiency in the country. FIPS stands for Federal Information Processing Series and was created to protect data privacy, digital security, etc.
  • There are nine digits in ZIP codes, whereas county FIPS codes do not have more than five digits.
  • ZIP codes denote a group of postal delivery routes. FIPS codes help identify a particular county or state and have nothing to do with any mailing routes.
  • Currently, there are 3,241 counties in the US with 3,241 FIPS codes. On the other hand, there are 41,692 ZIP codes.

However, there are some similarities between ZIP codes and FIPS codes. Both of these cross-city and state lines. Also, ZIP codes cross several counties and FIPS codes, and vice versa.

So, a single ZIP code could denote more than one county, and a single county could have more than one ZIP code passing through it.

After knowing these differences and similarities, the next thing you may think about is whether it’s possible to convert ZIP to FIPS codes.

Well, the answer is both yes and no. If you want to convert a ZIP code to FIPS code, you need to conduct a FIPS code lookup using ZIP code. But again, as discussed above, the process is hectic and inefficient.

In the same way, you may be curious to know if you could convert a FIPS code to ZIP code. Here, the answer is positive. You can easily find a list of all the ZIP codes in a particular county through its FIPS code.

Also Read: How Long Will Mail Take From Zip Code To Zip Code?

How to Become FIPS Compliant?

Now that you know so much about FIPS codes, let's learn about the features of a FIPS-compliant organization.

To become compliant with the FIPS code system, a company should follow all the prescribed computer system and data security standards.

The Federal Information Security Management Act of 2002 (FISMA) has laid down several standards and guidelines. This act helps federal government agencies in reducing information technology risks at reasonable costs.

However, the act was replaced by the Federal Information Security Modernization Act of 2014 (FISMA2014). It amended some elements of the FISMA to adapt to the changing needs in cybersecurity.

Now, the computer systems of government contractors and agencies must adhere to the FIPS publications 140, 180, 186, 197, 198, 199, 200, 201, and 202.

All these standards offer different levels of security and are used for various purposes. 

FIPS-compliant organizations can better prove that their products and services are secure, and their top priority is data privacy. 

So, apparently, FIPS codes are not just used to identify counties and states but also have several other purposes. Therefore, it is better to know how to find a FIPS code and their respective counties in this scenario.

PostGrid’s address verification API can help you find counties, cities, and states across the US. Hence, you can find locations with ease and without any confusion among county lines and state lines.

Also Read: How Long Does Regular Mail Take from State to State?

PostGrid’s Address Verification API and Software


As we saw earlier, conducting county code lookups using ZIP codes is difficult. So, what can we do to make the process simple for you?

PostGrid uses rooftop geocoding to find the exact physical address of a person. Hence, you can discover the FIPS codes of your customers in just a matter of minutes.

Address Autocomplete, Parsing, and Standardizing

Before validating mailing addresses, PostGrid conducts several processes like autocomplete, parsing, and standardization. These steps help make the address verification process faster and easier.

  • Address autocomplete is helpful to add missing address information and reduce the number of keystrokes needed to enter an address.
  • Parsing breaks down addresses to identify their parts like street addresses, city names, and so on.
  • Standardization helps you format postal addresses as per the address format and guidelines laid down by the USPS.

PostGrid carries out all these steps simultaneously to give you fully-verified mailing lists in very little time.

CASS-Verified Addresses

Our address verification API and software are CASS-certified. It means that PostGrid uses the USPS database to standardize and verify your mailing lists.

Our solutions make sure that your mailing lists are precise and that you can continue mailing with USPS. This way, you can skip worrying about lost or returned mail items.

Also, you can receive substantial postal discounts if your mailing addresses are verified.

International Mailing Address Validation

PostGrid can help you verify any local, national, or international address. So, you don’t need to restrict yourself to any borders. In fact, you can validate addresses of over 240 countries around the globe.

Also, PostGrid’s address verification API helps you transliterate mailing addresses in the destination country’s language. It also enables you to format addresses as per the country’s postal guidelines. So, you can mail to any location with complete accuracy and efficiency.

If you want to find FIPS codes, ZIP codes, or postal codes of other nations, your search stops here. PostGrid can help you find these elements and continue to expand your database.

Data Management and Enhancement

There are many things you can do to enhance and update your database, like:

  • Classifying addresses as residential and commercial.
  • Identifying and filtering out vacant, not-yet-built, and demolished addresses.
  • Segmenting mailing lists as per several demographics like age, gender, location, etc.
  • Accessing the National Change of Address (NCOA) database to record address changes.
  • Adding additional details like ZIP+4 codes, FIPS codes, DPV codes, etc.

What if we tell you that you can get all these things done without any manual effort on your part? Sounds exciting, right?

Well, PostGrid’s address validation API can help you complete these steps quickly. So, you can always have access to a fresh and up-to-date mailing list.

Set-Up and Installation

PostGrid offers easy-to-use solutions, and you can set up the API or software within minutes. However, if you face any issues, you can contact our technical support team at any time of the day.

Data Privacy and Security

FIPS standards are all about data privacy and security. Their prime purpose is to keep computer systems secure for data exchanges and other purposes.

So, we understand the importance of data confidentiality. Also, PostGrid is compliant with HIPAA, PIPEDA, and SOC-II, leaving no room for any privacy issues.


PostGrid offers two types of address verification- on-demand and bulk. Plus, our API is scalable and can process millions of API calls per second. So, it doesn’t matter if you want to look up one county or a thousand. PostGrid can help you do both.

API Integrations

You can start standardizing and validating mailing addresses on any platform you want. All you have to do is integrate our direct mail API into your CRM.

Fuzzy Matching

Fuzzy matching helps address validation vendors solve problems like:

  • Missing words
  • Vague abbreviations
  • Typos
  • Incorrect spacing and capitalization
  • Misspellings
  • Switched letters, etc.

These issues often make your postal addresses incorrect, invalid, and undeliverable. But, PostGrid uses the fuzzy matching logic to solve them and validate your addresses correctly.

The integration process does not require any technical expertise and can be completed effortlessly.

PostGrid also offers Zapier integration to help you connect with 1600+ apps. This way, you can expand your reach and get in touch with more prospects.

Wrapping Up

FIPS codes help make our lives easier by providing additional data security and confidentiality. These codes also help us identify counties and states distantly, and find exact locations for mailing purposes.

PostGrid can help you solve all your address verification and mailing needs. From finding the users’ exact locations to printing and mailing them direct mail assets, we can assist you through all of it.

Ready to find FIPS codes and verify mailing addresses in minutes? Sign up now!

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