Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

John P. Mcmahon, LCSW

Social Worker in Westborough, MA · enumerated 2007.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1548464092

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Registry record

Entity type Individual (Type 1)

Name John P. Mcmahon

Credential LCSW

Sex Male

Practice address 900 Union St, Westborough, MA, 01581

Phone (508) 898-2338

Fax (508) 366-9938

Enumeration date Jun 11, 2007

Last updated in NPPES Mar 26, 2019

Taxonomy & licenses

104100000X Social Worker Behavioral Health & Social Service Providers · License 213699 (MA) Primary

LCSW · Licensed Clinical Social Worker: A social worker licensed for clinical practice including mental-health therapy. About the LCSW credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What specialty is John Mcmahon?

John Mcmahon is registered in NPPES with the primary taxonomy of Social Worker. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2019-03-26.