Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Richard Joseph Chadwin, MD

Neurodevelopmental Disabilities Physician in Sonoma, CA · enumerated 2006.

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

National Provider Identifier

1811949399

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Registry record

Entity type Individual (Type 1)

Name Dr. Richard Joseph Chadwin

Credential MD

Sex Male

Practice address 690 Hudson Ct, Sonoma, CA, 95476

Phone (707) 849-6533

Enumeration date May 16, 2006

Last updated in NPPES May 22, 2018

Taxonomy & licenses

2084P0800X Psychiatry Physician Allopathic & Osteopathic Physicians · License G27274 (CA) Secondary

2084P0005X Neurodevelopmental Disabilities Physician Allopathic & Osteopathic Physicians · License G27274 (CA) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD 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

Where does Richard Chadwin practice?

The practice location on file with NPPES is in Sonoma, CA. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Richard Chadwin?

The National Provider Identifier (NPI) for Richard Chadwin is 1811949399, a Type 1 (individual) record in the CMS NPPES registry.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2018-05-22.