NPI Portal NPI Lookup & Verification

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

Ms. Mary Ann Dier - Zimmermann, L.C.P.C.

Professional Counselor in Bourbonnais, IL · enumerated 2007.

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

National Provider Identifier

1336298306

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Registry record

Entity type Individual (Type 1)
Name Ms. Mary Ann Dier - Zimmermann
Credential L.C.P.C.
Sex Female
Practice address Bourbonnais, IL, 60914
Phone (815) 573-1443
Enumeration date Jan 9, 2007
Last updated in NPPES Jul 25, 2023

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

Taxonomy & licenses

101YP2500X Professional Counselor Behavioral Health & Social Service Providers · License 180-001433 (IL) 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

What is the NPI number for Mary Dier - Zimmermann?
The National Provider Identifier (NPI) for Mary Dier - Zimmermann is 1336298306, a Type 1 (individual) record in the CMS NPPES registry.
Where does Mary Dier - Zimmermann practice?
The practice location on file with NPPES is in Bourbonnais, IL. Providers can have multiple locations; NPPES lists the primary practice address.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-07-25.