Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Dr. Mark D Hahn, O.D.
Optometrist in Washington, IL · enumerated 2005.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1528055969
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Registry record
Entity type Individual (Type 1)
Name Dr. Mark D Hahn
Credential O.D.
Sex Male
Practice address 8 Cherry Tree Center, Washington, IL, 61571
Phone (309) 444-2277
Fax (309) 444-2498
Enumeration date Sep 30, 2005
Last updated in NPPES Jan 4, 2014
Taxonomy & licenses
OD · Doctor of Optometry: A licensed optometrist providing primary vision care, eye exams, and corrective lenses.
About the OD credential
Other identifiers
| Identifier | Type | State | Issuer |
|---|---|---|---|
| 046009257 | Medicaid | IL | - |
| 410043928 | Other | IL | MEDICARE RAILROAD |
| 7215175 | Other | IL | BCBS |
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.
Frequently asked questions
Where does Mark Hahn practice?
The practice location on file with NPPES is in Washington, IL. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Mark Hahn?
The National Provider Identifier (NPI) for Mark Hahn is 1528055969, a Type 1 (individual) record in the CMS NPPES registry.
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2014-01-04.