JOAN M MCMAHON MD
NPI 1467403345
Internal Medicine in Lewistown, MT
About Joan M Mcmahon Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
JOAN M MCMAHON MD (NPI 1467403345) is an individual internal medicine provider in Lewistown, Montana, licensed in Montana (MED-PHYS-LIC-9666) and active in the NPI registry since May 2006. She is enrolled in Medicare PECOS.
NPPES Registry Identity
Specialties & Licenses 2
Other Identifiers 2
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare (PECOS)
Joan M Mcmahon Md is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).
Medicare Billing Reassignments
6Medicare enrollment records show Joan Mcmahon reassigns Medicare billing to 6 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Lewistown, MT 59457
- Reassigned Medicare billing, Montana enrollment
- 83 clinicians in this Medicare group
Lewistown, MT 59457
- Reassigned Medicare billing, Montana enrollment
- 40 clinicians in this Medicare group
Lewistown, MT 59457
- Reassigned Medicare billing, Montana enrollment
- Medicare enrollment name: Central Montana Community Health Center, Inc.
- 8 clinicians in this Medicare group
Harlowton, MT 59036
- Reassigned Medicare billing, Montana enrollment
- 31 clinicians in this Medicare group
Billings, MT 59102
- Reassigned Medicare billing, Montana enrollment
- 1,264 clinicians in this Medicare group
Townsend, MT 59644
- Reassigned Medicare billing, Montana enrollment
- Also billed through NPI 1447245857 (Montana)
- 65 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 59457 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Referred Medical Equipment & Supplies CMS DME claims 5
Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
LEWISTOWN, MT 59457
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Joan Mcmahon's NPI number?
The NPI number for Joan Mcmahon is 1467403345. It was assigned to this individual provider in the NPPES registry on May 15, 2006.
Where is Joan Mcmahon located?
Joan Mcmahon practices at 408 Wendell Ave, Lewistown, MT 59457. The listed phone number is (406) 535-1502.
What is Joan Mcmahon's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is Joan Mcmahon enrolled in Medicare?
Yes. Joan Mcmahon is registered in the Medicare PECOS enrollment system.
Which organizations bill Medicare for Joan Mcmahon's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Joan Mcmahon reassigns Medicare benefits to 6 organizations: Central Montana Medical Facilities, Inc. (Lewistown, MT), State Of Montana (Lewistown, MT), Bighorn Valley Health Center Incorporated (Lewistown, MT), Wheatland Memorial Healthcare (Harlowton, MT), Billings Clinic (Billings, MT) and 1 more organization, listed in the Medicare section above. Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Joan Mcmahon's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Joan Mcmahon accept?
Health plans from Blue Cross and Blue Shield of Montana, Mountain Health CO-OP and Providence Health Plan list Joan Mcmahon as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
When was this NPI record last updated?
The NPPES record for Joan Mcmahon was last updated on June 19, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Joan M Mcmahon, MD · NPI 1467403345
Internal Medicine physician in Lewistown, Montana. Individual provider, active in the CMS NPPES registry since May 15, 2006.
## Identity
- **NPI:** 1467403345 (Entity type: Individual)
- **Enumerated:** May 15, 2006
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** MED-PHYS-LIC-9666 (Montana)
- **Sole proprietor:** No
## Practice location
- **Address:** 408 WENDELL AVE, Lewistown, MT 59457-2261
- **Phone:** (406) 535-1502
## Medicare
- **Medicare:** Enrolled in Medicare (PECOS)
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 6 organizations under Medicare reassignment (form CMS-855R): Central Montana Medical Facilities, Inc. (NPI 1427161843, Lewistown, MT); State Of Montana (NPI 1528079720, Lewistown, MT); Bighorn Valley Health Center Incorporated (NPI 1942450432, Lewistown, MT); Wheatland Memorial Healthcare (NPI 1073687406, Harlowton, MT); Billings Clinic (NPI 1427262898, Billings, MT); and 1 more · CMS Revalidation Reassignment List, October 2026 release
## Record status
- **NPPES last updated:** June 19, 2024
- **Other identifiers:** Medicaid 0029206 (MT); Other 810536408 (MT)
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Source: [NPI Profile](https://npiprofile.com/npi/1467403345) · Data from the CMS NPPES public registry.