Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Matthew Garthwait

Clinical Social Worker in Rye, NH · enumerated 2016.

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

National Provider Identifier

1578929337

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Registry record

Entity type Individual (Type 1)

Name Matthew Garthwait

Sex Male

Practice address Rye, NH, 03870

Phone (603) 969-7842

Enumeration date Jan 11, 2016

Last updated in NPPES Jan 14, 2026

Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 2399 (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.

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Frequently asked questions

Is NPI 1578929337 active?

Yes — as of the latest NPPES snapshot, NPI 1578929337 is active (record last updated 2026-01-14).

How do I verify Matthew Garthwait's NPI record?

Cross-check NPI 1578929337 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Other providers at this practice address

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Cynthia Bear Gynecology Physician · Rye, NH NPI 1033173992 Cynthia M Bear, MD, Pllc Gynecology Physician · Rye, NH NPI 1851578926 Wendy Mclaughlin MD Pllc Gynecology Physician · Rye, NH NPI 1992025076 Cecelia Tarr Clinical Social Worker · Rye, NH NPI 1487133815 Sheri Flaherty Mental Health Counselor · Rye, NH NPI 1629545181 Elian Beattie Therapy LLC Dba Insights Training Group Mental Health Clinic/Center (Including Community Mental Health Center) · Rye, NH NPI 1568212777 Laura Trachtenberg Mental Health Counselor · Rye, NH NPI 1407798093

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-01-14.