Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dennis S O'Brien, MD

Internal Medicine Physician in Ticonderoga, NY · enumerated 2007.

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

National Provider Identifier

1952449829

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Registry record

Entity type Individual (Type 1)

Name Dennis S O'Brien

Credential MD

Sex Male

Practice address 102 Race Track Rd Ste 1, Ticonderoga, NY, 12883

Phone (518) 585-6708

Fax (518) 585-3260

Enumeration date Feb 2, 2007

Last updated in NPPES Nov 9, 2018

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 154766 (NY) 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
00774992	Medicaid	NY	-

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 1952449829 active?

Yes, as of the latest NPPES snapshot, NPI 1952449829 is active (record last updated 2018-11-09).

How do I verify Dennis O'Brien's NPI record?

Cross-check NPI 1952449829 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2018-11-09.