Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Gavin O'Brien, LICSW

Clinical Social Worker in Londonderry, NH · enumerated 2006.

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

National Provider Identifier

1659431211

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Registry record

Entity type Individual (Type 1)

Name Gavin O'Brien

Credential LICSW

Sex Male

Practice address 25 Nashua Rd Unit A1, Londonderry, NH, 03053

Phone (978) 276-4227

Enumeration date Dec 12, 2006

Last updated in NPPES Oct 12, 2026

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 1838 (NH) Primary

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

Is NPI 1659431211 active?

Yes, as of the latest NPPES snapshot, NPI 1659431211 is active (record last updated 2026-10-12).

How do I verify Gavin O'Brien's NPI record?

Cross-check NPI 1659431211 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Alexandra Baltimore Clinical Social Worker · Londonderry, NH NPI 1073801007 Sabrinna Kay Mental Health Counselor · Londonderry, NH NPI 1841806106 Allied Counseling for Women, LLC Mental Health Counselor · Londonderry, NH NPI 1396453940 Valor Counseling and Consulting Mental Health Counselor · Londonderry, NH NPI 1871423483

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-10-12.