Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

William J Mathias, LCSW

Clinical Social Worker in Green Bay, WI · enumerated 2006 · practices at Psychologie Clinique Sc.

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

National Provider Identifier

1912071101

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name William J Mathias

Credential LCSW

Sex Male

Practice address 130 E Walnut St, Suite 706, Green Bay, WI, 54301

Phone (920) 437-8256

Fax (920) 437-1188

Enumeration date Nov 20, 2006

Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 2091-123 (WI) Primary

LCSW · Licensed Clinical Social Worker: A social worker licensed for clinical practice including mental-health therapy. About the LCSW credential

Other identifiers

Identifier	Type	State	Issuer
39257500	Medicaid	WI	-

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 this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is William Mathias?

William Mathias is registered in NPPES with the primary taxonomy of Clinical Social Worker. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.