Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Joan M McMahon, MD

Individual provider Hospitalist Physician · NPI 1467403345

Joan M McMahon, MD is an Internal Medicine in Lewistown, Montana. Graduated from Saint Louis University School of Medicine in 1996, 30 years ago. Practices with Central Montana Medical Facilities Inc, a 26-clinician group and accepts Medicare assignment. Licensed in Montana.

Years since qualifying
30
Trained at
Saint Louis University School of Medicine
Licensed in
MT
In the registry since
2006
Specialties on file
2
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

408 Wendell Ave
Lewistown, MT 59457-2261
Phone: (406) 535-1502
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence MED-PHYS-LIC-9666 (MT)
Hospitalist Physician Taxonomy 208M00000X · Licence MED-PHYS-LIC-9666 (MT)

Record details

NPI number1467403345
Entity typeIndividual (Type 1)
GenderFemale
Credentials MD
Sole proprietorNo
NPI enumeratedMay 15, 2006
Last updated in NPPESJune 19, 2024
Certification dateJune 19, 2024
Mailing address310 Wendell Ave, Att: Clinic Manager, Lewistown, MT 59457-2267

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Also practisesEMERGENCY MEDICINE, PEDIATRIC MEDICINE
Medical schoolSAINT LOUIS UNIVERSITY SCHOOL OF MEDICINE
Graduated 1996 (30 years in practice)
Group practice Central Montana Medical Facilities Inc — 26 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount