Pet Microchips in the United States: Databases, Registration and Tracing

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Last updated: 9 August 2026

Pet microchips in the United States are registered with private recovery services. There is no single national database containing every pet registration.

A record may be held by a microchip company, an independent registry, a shelter, a local authority or another pet-recovery service.

Having a microchip implanted is not enough. The number must also be linked to the owner’s current contact details.

This guide explains how pet microchip registration works in the United States, which registries may hold the record, how US and foreign chip numbers can look, and what to do if a microchip is not found.

Use it to check the right tracing routes, understand AAHA and private registry searches, and prepare the documents you may need as a pet owner, finder, adopter or rescuer.

In this guide:

ChipTrace can help you check available databases, identify possible country, registry or manufacturer clues, and decide the next tracing step.

What do US microchip numbers look like?

Most modern pet microchips follow the ISO standard and contain 15 digits.

Some older chips contain 9 or 10 digits.

The official ISO numeric country code for the United States is 840.

A country-coded microchip can begin with 840, but this is not the most common format for everyday pet dogs and cats in the United States. In practice, many US pets have manufacturer-coded microchips instead.

Manufacturer-coded microchips start with the digit 9. These numbers may be used in several countries, so they do not prove where the pet was chipped or registered.

Some animals were chipped in another country before moving to the United States.

This is common with:

  • Imported dogs and cats
  • Pets adopted through foreign rescues
  • Animals that moved with their families
  • Pets that previously lived in Canada or Mexico
  • Older animals with non-standard chip formats

A readable foreign or manufacturer-coded chip can still be registered with a US registry.

In short, the first digits can give a clue about origin. They do not prove where the animal lives or which registry holds the record.

Example formats commonly found in the United States

Many different microchip numbers are used in the US. These examples show common patterns, but many other variations exist.

  • 840123456789012 — US country-coded microchip, less common for everyday pet dogs and cats
  • 985123456789012 — manufacturer-coded microchip
  • 982123456789012 — manufacturer-coded microchip
  • 977123456789012 — manufacturer-coded microchip
  • 380123456789012 — foreign country-coded microchip

Read our guide to pet microchip numbers for more detailed information and practical steps.

What should you do if you find a pet with a US microchip number?

Follow these quick tracing steps to help reunite the animal with its owner.

  1. If you are in the United States and find an animal that appears lost, ask a vet, shelter, rescue or animal-control service to scan the animal and confirm the full microchip number.
  2. Use ChipTrace to check available US and international routes, including 100+ databases worldwide.
  3. Use the AAHA Microchip Registry Lookup as an important US cross-registry search route.
  4. Contact the registry shown in the AAHA result. If several registries appear, start with the first one listed.
  5. Check databases in Canada, Mexico or another country where the animal may have lived.
  6. Contact any vet, shelter, rescue or breeder that may be connected to the animal.

ChipTrace checks connected US and international search routes. This may include PetLink US through PetMaxx, Animal-ID Global Search and other connected services.

AAHA remains an important separate US lookup route. It may show one registry, several possible registries, or a manufacturer or distributor route.

Remember: many owned cats in the United States are allowed to roam near their homes. Do not assume every outdoor cat is lost. Look for signs that the animal is injured, frightened, displaced or unfamiliar with the area before taking further action.

What happens after a US microchip result is found?

A successful search may show which registry holds the record. Do not expect to receive the owner’s private details directly.

The registry, vet, shelter, rescue or animal-control service can then help contact the registered owner.

If the owner cannot be reached, you can post on local social media and leave leaflets at veterinary clinics and shelters. Do not publish the complete microchip number online. Share only part of it so ownership claims can be checked safely.

Read Found a Microchipped Pet? What to Do Next for practical advice.

What if the microchip number is not found in any database?

Start by asking a vet, shelter, rescue or animal-control service to scan the animal again and confirm every digit. One wrong digit can return no result.

Possible causes and next steps:

  • The chip was implanted but never registered. Ask the vet, breeder, shelter or rescue to check their records.
  • Someone entered the number incorrectly. Re-scan the animal and search again with the verified number.
  • The registration is very recent. Ask the registry when the record should appear, then try again later.
  • The registry does not take part in AAHA. Use ChipTrace for other database, country, manufacturer or distributor clues.
  • The registry is temporarily unavailable or has closed. Try again later and contact the manufacturer or distributor.
  • The animal is still registered in another country. Check databases in countries where the animal may have lived.

Extra tracing routes to try

  • Use ChipTrace again after confirming the number. It can also suggest a likely country, manufacturer or distributor, including contact information where available.
  • Use the AAHA Microchip Registry Lookup again.
  • Check databases in Canada, Mexico or another country where the animal may have lived.
  • Contact the microchip manufacturer or distributor. They may identify the distributor who sold the chip and the vet, breeder or rescue that received it.

You can use the email template ChipTrace creates to contact manufacturer/distributor when no registration is found.

Manufacturers and distributors normally do not give out the owner’s private details. Instead, they may identify the distributor that supplied the chip, the vet or organisation that received it, or pass a matched enquiry to the next organisation.

Finding the owner is not guaranteed, but these extra steps often help. If you still cannot trace the owner after checking every route, contact a local shelter, rescue or animal-control service for advice.

Read our guide to why a microchip may not appear in any database.

Check a Microchip

Which microchip registries are used in the United States?

The United States uses many private microchip registries.

Some are operated by microchip manufacturers. Others are independent pet-recovery services. Some shelters, clinics and local authorities may also keep local records.

Common registries include:

  • 24Petwatch
  • AKC Reunite
  • HomeAgain
  • PetLink
  • Petkey
  • Michelson Found Animals Registry
  • Registries in Canada, Mexico or another country

This is not a complete list.

An animal may appear in one registry but not another. The company that supplied the microchip often decides where the first record is created.

Updating one registration does not normally update another registration. Ask the vet, shelter, breeder or rescue which registry was used.

Can the public search US microchip registries?

Yes, but not through one single national database.

The AAHA Microchip Registry Lookup is the main US cross-registry lookup route. It searches participating registries and may identify which registry has information linked to the microchip number.

The lookup should not show the owner’s full private details.

The finder must contact the registry or ask an authorised organisation for help. A vet, shelter, rescue or animal-control service may have more tracing options.

What is the AAHA Microchip Registry Lookup?

AAHA stands for the American Animal Hospital Association.

Its free lookup searches participating microchip registries.

It accepts microchip numbers containing 9, 10 or 15 digits. Enter the number without spaces or punctuation.

The lookup may show:

  • A registry holding the record
  • More than one possible registry
  • The most recently updated registry first
  • A microchip manufacturer or distributor

The lookup does not:

  • Show the owner’s private information
  • Register a microchip
  • Update an existing record
  • Search every registry in the world

When several registries appear, contact the first one listed. Continue down the list when needed.

A negative result does not prove that the microchip is unregistered. Not every registry takes part in the AAHA lookup.

How does ChipTrace search the United States?

ChipTrace checks available US and international search routes where possible.

This may include:

  • PetLink US through PetMaxx
  • Animal-ID Global Search, which includes AAHA
  • Other connected international database routes

At the same time, ChipTrace checks 100+ registries and databases worldwide.

This increases the chance of finding a registration, especially when a pet was imported, adopted through a rescue, moved between countries or has a manufacturer-coded chip.

For US microchips, AAHA is also useful as a separate manual search route. ChipTrace may provide a direct button or link for that search, but the user completes the manual AAHA search separately.

ChipTrace shows which databases and services were checked. It does not reveal the registered owner’s private contact details. A registry, vet, shelter, rescue, animal-control service or other authorised organisation must contact the owner.

Read how ChipTrace works for more information about database checks and next-step advice.

Do US states have their own microchip registries?

Usually, no.

The United States does not normally use one official microchip registry for each state. Most records are held by private recovery services.

Some cities, counties and animal-control departments also keep local records.

These records may be linked to:

  • Pet licensing
  • Animal-control services
  • Local shelters
  • Municipal lost-pet systems

A local record can be useful. However, it should not replace registration with a reliable recovery registry.

The main registration should be easy to identify through AAHA or another common lookup route.

Are microchips required in the United States?

There is no single federal rule requiring every privately owned dog and cat to have a microchip.

State, county and city rules can be different.

Some local authorities require microchipping in certain situations. Shelters and rescue groups may also require it before adoption.

A microchip may be required after:

  • Adoption from a public shelter
  • A dog being declared dangerous
  • An animal being reclaimed from animal control
  • Registration under a local breeding rule
  • International travel

Ask a local vet or animal-control service which rules apply where the animal lives.

Does the pet also need a local licence?

Possibly.

Many cities and counties require dogs to have a local licence. Some places also license cats.

A pet licence and a microchip registration are separate records.

You may therefore need to:

  • Register the microchip with a recovery service
  • Buy or renew a city or county pet licence
  • Update both records when your details change

Do not assume that updating one system will update the other.

Are cats required to be microchipped?

There is no general federal rule requiring every privately owned cat to have a microchip.

State or local rules may be different.

Microchipping and registration are still strongly recommended. An indoor cat can also escape, and a registered microchip gives a finder another route back to the owner.

Cats travelling internationally may need a readable ISO-compatible microchip.

Who can implant a microchip?

A trained professional should implant the chip. This is usually a vet, shelter professional, animal-control professional or another trained implanter.

The professional should confirm the complete number after implantation.

Remember: implanting and registering are separate steps. The microchip itself holds only an identification number. Owner contact details are stored in the registry or database.

A working chip may still be difficult to trace if no one completed the registration.

How to register a pet microchip in the United States

A vet, shelter, breeder or rescue may create the first registration. In other cases, the owner must complete it.

To register a pet:

  1. Confirm the complete microchip number.
  2. Use ChipTrace or AAHA to identify the registry where possible.
  3. Contact the registry through its official website.
  4. Create or claim the animal’s record.
  5. Add information about the animal.
  6. Add your current address and contact details.
  7. Add an emergency contact when possible.
  8. Provide proof of ownership when requested.
  9. Pay any required registration or transfer fee.
  10. Keep the confirmation and account details.

Useful documents may include:

  • The microchip certificate
  • Vet records
  • An adoption contract
  • A purchase agreement
  • A transfer code or form
  • A previous registration certificate
  • A foreign registration document
  • A local pet licence

Some registries provide free basic registration. Others charge a one-time or recurring fee. Check what is included before paying.

Does the vet, shelter or breeder register the chip automatically?

Not always.

A clinic may create the first record when the chip is implanted. A shelter or rescue may begin the process before adoption. A breeder may register the chip before a puppy moves to its new home.

However, the new owner may still need to claim or transfer the record.

Ask:

  • Which registry holds the record?
  • Has the first registration been completed?
  • Who is currently named on the record?
  • Do I need a transfer code?
  • Do I need to create an account?
  • Are there any fees?

Do not assume that implantation means the registration is complete. A chip without current contact details may not lead a finder back to you.

Does the chip have to be registered with its manufacturer?

Not always.

A microchip is often first registered with a service linked to its manufacturer or distributor. However, some owners use an independent registry.

The important points are that the registry:

  • Can be found through common lookup tools
  • Stores current contact details
  • Responds when a lost pet is found
  • Allows the owner to update the record

Keep a note of every registry where the microchip is active.

Can I add a global microchip registration?

Yes. An additional global registration can provide another route back to the owner.

Animal-ID allows owners to create a free extra record using an existing microchip number.

This may help when:

  • The pet travels outside the United States
  • The animal was first registered in another country
  • A finder uses an international search service
  • The main US registry becomes unavailable
  • The animal has a foreign or manufacturer-coded chip

Important: an extra global registration is a safety net. It does not replace the main US registration or any required local licence.

Updating Animal-ID does not update the US registry. Keep the same contact details in every active database.

How to check your pet’s microchip registration

This section is for owners who already know their pet’s microchip number.

If you do not know the microchip number, ask a vet, shelter or rescue to scan the animal first.

To check the registration:

  • Use ChipTrace to check available US and international routes.
  • Use the AAHA Microchip Registry Lookup.
  • Contact the registry named in the result.
  • Sign in to the registry’s owner account.
  • Compare the number with the microchip certificate and vet records.
  • Check any foreign database where the pet was previously registered.

When checking, confirm the registered owner’s name, address, telephone number and email address.

Also check that the animal’s status is correct. It should not still be marked as missing, stolen, transferred or deceased.

A public lookup may identify the registry without showing your personal information. This is normal.

What if the registry has closed?

The microchip does not stop working when a registry closes. However, the owner record may no longer be available through that company.

Use the confirmed microchip number to:

  • Search through ChipTrace
  • Search the AAHA lookup
  • Check whether another registry holds a record
  • Register the existing chip with a reliable active service

The microchip does not normally need to be removed or replaced. Keep the new registration confirmation.

How to update a US microchip registration

Contact every registry holding an active record.

Update the registration when:

  • You move home
  • Your telephone number changes
  • Your email address changes
  • The emergency contact changes
  • The animal moves to a new owner
  • The animal goes missing
  • The animal is found again
  • The animal moves abroad
  • The animal dies

Most registries allow some changes through an online account. Other changes may require a telephone call or documents.

Updating vet records does not update the microchip registry. Update any city or county licence separately.

Update foreign and international registrations separately. Check the microchip record at least once a year.

What happens when you move to another state?

You normally do not need to change registries simply because you move to another state.

Update the existing record with your new address and contact details.

Also check the pet-licensing rules in your new city or county. Local licensing and microchip registration are separate systems.

How to transfer a US microchip registration

The registration must be changed when a pet moves to a new owner.

The process depends on the registry. The previous owner may need to start or approve the transfer. The new owner may need to provide documents.

Useful documents may include:

  • An adoption contract
  • A purchase agreement
  • A transfer code or signed form
  • Vet records
  • The microchip certificate
  • Written confirmation from the previous owner
  • Your identification

After the transfer, check your name, address, telephone number and email address.

Update any local pet licence separately.

What if the pet is still registered to someone else?

Contact the previous owner, shelter, rescue or breeder first.

Ask them to start or approve the transfer.

If they cannot help, contact the registry directly. Explain how the animal came into your care.

The registry may ask for:

  • An adoption contract
  • A purchase receipt
  • A signed transfer form
  • Vet records
  • Proof that you tried to contact the previous owner
  • Proof that the animal is now in your care

Do not create false information or a conflicting registration.

A registry record shows who is registered as the animal’s contact. It may not settle a legal disagreement about ownership.

Buying or adopting a pet in the United States

Ask for the complete microchip number before taking the animal home.

Ask a vet, shelter or rescue to check the microchip when possible.

Make sure the number matches every document.

Also ask for:

  • The name of the microchip registry
  • The registration certificate
  • A transfer code or form
  • Vet and vaccination records
  • An adoption contract or purchase agreement
  • Information about any local pet licence
  • Information about any foreign registration

The previous owner, breeder, shelter or rescue should help transfer the record.

What about a pet adopted from a foreign rescue?

Ask the rescue which registrations already exist.

Also ask:

  • Whether the animal has been checked for a microchip
  • Who is named in the foreign registration
  • Which database holds the record
  • Who will update the existing registration
  • Who will create or confirm the US registration
  • Whether the rabies and import documents are complete

A foreign registration does not automatically create a US record.

Keep the foreign registration active until the US record has been confirmed.

What should you do if your pet goes missing?

Contact every microchip registry holding an active record.

Ask for the animal to be marked as missing. Also check that your telephone number and email address are correct.

Also:

  • Contact local shelters
  • Contact animal-control services
  • Contact nearby vet clinics
  • Contact rescue groups
  • Check local lost-and-found pet pages
  • Share a clear photograph and the area where the animal disappeared

Do not publish the complete microchip number online. If someone finds your pet, another person could copy the full number from your public post and try to claim the animal as theirs.

Share only part of the microchip number publicly. Keep the full number for vets, shelters, animal-control services, the registry and trusted organisations helping with the search.

When the animal returns, close every missing-pet report.

Bringing an imported pet to the United States

A foreign registration does not automatically create a US record.

A readable foreign or manufacturer-coded chip normally does not need to be replaced.

Ask a US vet to check the microchip and documents after arrival.

Take:

  • The animal
  • Its passport or official health certificate
  • Its rabies vaccination record
  • The microchip certificate, when available
  • Your US address and contact details
  • Any foreign registration documents
  • An adoption or transfer document, when relevant

Check that the microchip number matches every document.

Add the existing number to a suitable US recovery registry.

Keep the foreign registration active until the US record has been confirmed. Then update the foreign record with your new contact details when possible.

Animals entering the United States may need to meet federal and state rules. The requirements depend on the species, country of origin and recent travel history.

What are the US entry requirements for dogs?

All dogs entering or returning to the United States must normally:

  • Appear healthy when they arrive
  • Be at least six months old
  • Have a microchip that can be read with a universal scanner
  • Travel with a CDC Dog Import Form receipt

The microchip number must match the number on the travel documents.

Dogs that have been in a high-risk dog-rabies country during the previous six months need extra documents.

A foreign-vaccinated dog from a high-risk country may need:

  • A valid foreign rabies vaccination certificate
  • A microchip recorded before the rabies vaccination
  • A rabies antibody blood test
  • A booking at a CDC-registered animal care facility

The exact route depends on the dog’s vaccination history and recent travel.

Check the latest CDC dog-entry guidance before travelling.

Also check any state entry rules.

Travelling abroad from the United States

Microchip registration and border rules are separate.

Every destination country has its own pet-entry rules.

A pet may need:

  • A readable ISO-compatible microchip
  • A valid rabies vaccination
  • A rabies antibody blood test
  • A veterinary health certificate
  • USDA endorsement
  • Parasite treatment
  • An import permit or advance notice

Some steps must be completed in a strict order. Many countries require the microchip to be implanted before the rabies vaccination used for travel.

A USDA-accredited vet can prepare any required export health certificate. USDA APHIS may then need to endorse it.

Start preparing early. Use the USDA APHIS Pet Travel website to check the destination rules.

Travelling from the United States to the European Union

Dogs, cats and ferrets travelling from the United States to the EU normally need:

  • A readable ISO-compatible microchip
  • A rabies vaccination given after identification
  • The correct EU animal health certificate
  • USDA endorsement of the certificate
  • Entry through an approved travellers’ point
  • Tapeworm treatment for dogs entering certain countries

The United States is normally treated as a listed country for EU pet travel.

A rabies antibody blood test is therefore not normally required for a standard direct non-commercial journey from the United States to the EU.

The health certificate must be completed and endorsed before departure.

Check the destination country’s current rules before travelling.

AAHA Microchip Registry Lookup
Identify a participating registry connected to a microchip

CDC dog-entry guidance
Check current rules for bringing a dog into the United States

USDA APHIS Pet Travel
Check official import and export requirements

Animal-ID
Create an additional global microchip registration