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

Dr. William L Nelson, D.C.

Chiropractor in Diamond Bar, CA · enumerated 2007.

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

National Provider Identifier

1366581621

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Registry record

Entity type Individual (Type 1)

Name Dr. William L Nelson

Credential D.C.

Sex Male

Practice address Diamond Bar, CA, 91765

Phone (909) 860-1301

Fax (909) 860-1330

Enumeration date Feb 5, 2007

Last updated in NPPES Sep 7, 2023

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

Taxonomy & licenses

111N00000X Chiropractor Chiropractic Providers · License DC 21597 (CA) Primary

DC · Doctor of Chiropractic: A licensed chiropractor focusing on musculoskeletal and nervous system disorders. About the DC 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 William Nelson practice?

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

What is the NPI number for William Nelson?

The National Provider Identifier (NPI) for William Nelson is 1366581621, a Type 1 (individual) record in the CMS NPPES registry.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-09-07.