NPI lookup by state
NPI lookup by state
The CMS NPI Registry does not answer a state-only search, so there is no free official way to list every NPI in a state. Verified against the official registry API on 2026-07-30, a state-only query is rejected with error 07, “Field state requires additional search criteria.” Each state page below issues the query that isaccepted — the state paired with a provider taxonomy — and shows the exact official URL behind every record.
State-only search
Refused (error 07)
The registry requires additional search criteria alongside a state, so a state page is never a complete directory.
What works instead
State + taxonomy
state=TX with taxonomy_description=Physician Assistant returns records; city, postal code, and name also narrow a state.
Response ceiling
200 records
limit=201 and limit=1500 both returned exactly 200 rows, so a single response is never a complete count.
Source citation
What a state-scoped NPI lookup can return
Last verified: 2026-07-30. date_retrieved: 2026-07-30. Each row records what the official CMS NPI Registry API returned for that query on that date, so a search that cannot be run is stated as plainly as one that can.
| Query | What the official registry returned | What it means |
|---|---|---|
| state only | Rejected: error 07, “Field state requires additional search criteria”. | No page anywhere can enumerate a state from this API. |
| state + taxonomy_description | Returns records, e.g. state=TX with taxonomy_description=Physician Assistant. | This is the query every state page here is built on. |
| any query, large limit | Capped at 200 rows; limit=201 and limit=1500 both returned exactly 200. | A sample, never a count. Page with skip to walk a larger set. |
| no version parameter | Rejected: error 17, “Unsupported Version”. | A request without an explicit version fails rather than defaulting. |
State pages
Each page below runs live state-plus-taxonomy queries against the official registry and links every record to its full NPI profile. These states are published first because they carry measured state-scoped NPI lookup demand; every other state is still served by the official registry search above and by the OIG exclusion index, which does cover all 50 states and DC.
Narrow by taxonomy
Specialty is the parameter that unlocks a state
Because a state cannot stand alone, the taxonomy is what makes a state-scoped query legal. These taxonomy pages run the same search nationwide and link back into every state page.
Reviewed by SourceCheck Health
Last reviewed: 2026-07-30. date_retrieved: 2026-07-30.
The registry behaviour recorded on this page is re-issued against the official CMS NPI Registry API before the state-scoped lookup guidance is updated. Registry taxonomy is CMS classification, not licensure, credentialing, Medicare enrollment, or current practice authority.
FAQ
Practical notes
Can I look up all NPI numbers in a state?
No. Verified against the official CMS NPI Registry API on 2026-07-30, a state-only query is rejected with error 07, "Field state requires additional search criteria". A state has to be paired with a taxonomy, city, postal code, or provider name, and a single response returns at most 200 records, so no free official query returns a complete state list.
How do I search NPI numbers in Texas?
Pair Texas with something else the registry accepts. The state pages here issue state plus taxonomy_description queries against the official API — for example state=TX with taxonomy_description=Physician Assistant — and show a dated sample of what the registry returned, along with the exact API URL used.
Why are only some states published here?
Each published state page is backed by live official-registry queries and is seeded in the sitemap, so the set is kept to states with measured lookup demand rather than fanned out to all 51. For any state, the official NPI Registry search and the state OIG exclusion index remain available.
Does a state NPI page show licensure or exclusion status?
No. Registry taxonomy is the classification CMS publishes, not licensure, credentialing, Medicare enrollment, or current practice authority. Exclusion status is a separate federal source: use the state OIG LEIE index for that.