NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Wilhelm Leonard Castellon

Internal Medicine Physician in Clarion, PA · enumerated 2015.

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

National Provider Identifier

1821471327

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)
Name Wilhelm Leonard Castellon
Sex Male
Practice address 24 Doctors Ln, Suite 202, Clarion, PA, 16214
Phone (814) 226-2500
Fax (814) 226-2501
Enumeration date Jul 1, 2015
Last updated in NPPES May 16, 2023

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License U2802 (TX) Primary
207Q00000X Family Medicine Physician Allopathic & Osteopathic Physicians · License OT016669 (PA) Secondary

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 Wilhelm Castellon practice?
The practice location on file with NPPES is in Clarion, PA. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Wilhelm Castellon?
The National Provider Identifier (NPI) for Wilhelm Castellon is 1821471327, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-05-16.