Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Dennis G O'Neill, M.D.

Anatomic Pathology & Clinical Pathology Physician in Manchester, CT · enumerated 2006.

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

National Provider Identifier

1083679021

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Registry record

Entity type Individual (Type 1)

Name Dr. Dennis G O'Neill

Credential M.D.

Sex Male

Practice address 71 Haynes St, Manchester, CT, 06040

Phone (860) 647-6487

Fax (860) 647-6447

Enumeration date Apr 20, 2006

Last updated in NPPES Oct 24, 2014

Taxonomy & licenses

207ZP0102X Anatomic Pathology & Clinical Pathology Physician Allopathic & Osteopathic Physicians · License 023300 (CT) 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
001233006	Medicaid	CT	-
A524580	Other	CT	OXFORD
OR4388	Other	CT	HEALTHNET
008172967	Other	CT	AETNA/USHC
W1H29	Other	CT	EMPIRE BC/BS
500HBL161CT01	Other	CT	BLUE CROSS MMH
76164901	Other	CT	CONNECTICARE
0004300173	Other	CT	AETNA
1104296	Other	CT	UHC
0102330	Other	CT	CIGNA
500HBL161CT02	Other	CT	BLUE CROSS RGH
C009784	Other	CT	CHAMPUS TRICARE

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.

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Frequently asked questions

Where does Dennis O'Neill practice?

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

What is the NPI number for Dennis O'Neill?

The National Provider Identifier (NPI) for Dennis O'Neill is 1083679021, 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 2014-10-24.