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Mary K O'Callaghan Do PC

Internal Medicine Physician in Ludington, MI · enumerated 2007 · authorized official Mary O'Callaghan, Physician.

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

National Provider Identifier

1467650614

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Registry record

Entity type Organization (Type 2)
Legal business name Mary K O'Callaghan Do PC
Practice address 922 Lawndale St, Ludington, MI, 49431
Phone (231) 845-7380
Enumeration date Jul 10, 2007
Last updated in NPPES Mar 7, 2023

Taxonomy & classification

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 009391 (MI) Primary

Authorized official

Name Mary O'Callaghan
Title Physician
Phone (231) 845-7380

Other identifiers

Identifier Type State Issuer
5530004 Other MI BCBS #
DG2738 Other MI MEDICARE RR GROUP
2736118 Medicaid MI —
1155300045 Other MI BC GROUP

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

Where is Mary K O'Callaghan Do PC located?
The practice location on file with NPPES is in Ludington, MI.
How current is this record?
Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2023-03-07. Verify at npiregistry.cms.hhs.gov.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-03-07.