Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Dennis Obrien, MD

Neurology Physician in Billings, MT · enumerated 2005.

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

National Provider Identifier

1811981699

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Registry record

Entity type Individual (Type 1)

Name Dr. Dennis Obrien

Credential MD

Sex Male

Practice address 801 N 29th St, Billings, MT, 59101

Phone (406) 238-2500

Enumeration date Sep 7, 2005

Last updated in NPPES Dec 11, 2014

Taxonomy & licenses

2084N0400X Neurology Physician Allopathic & Osteopathic Physicians · License 36099965 (IL) 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
000098136	Other	MT	BCBS PIN

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

Where does Dennis Obrien practice?

The practice location on file with NPPES is in Billings, MT. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Dennis Obrien?

The National Provider Identifier (NPI) for Dennis Obrien is 1811981699, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2014-12-11.