Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Thomas J Mcmahon, MD

Surgery Physician in Anaconda, MT · enumerated 2006.

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

National Provider Identifier

1558399709

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name Dr. Thomas J Mcmahon

Credential MD

Sex Male

Practice address 305 W Pennsylvania Ave, Anaconda, MT, 59711

Phone (406) 563-8571

Fax (406) 563-8523

Enumeration date Jun 28, 2006

Last updated in NPPES Jan 12, 2024

Taxonomy & licenses

208600000X Surgery Physician Allopathic & Osteopathic Physicians · License 8098 (MT) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier	Type	State	Issuer
1558399709	Other	MT	NPI

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.

Read the full guide → Validate an NPI →

Frequently asked questions

Is NPI 1558399709 active?

Yes, as of the latest NPPES snapshot, NPI 1558399709 is active (record last updated 2024-01-12).

How do I verify Thomas Mcmahon's NPI record?

Cross-check NPI 1558399709 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-01-12.