Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. William C Holohan, D.D.S.

Dentist in Northbrook, IL · enumerated 2007.

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

National Provider Identifier

1396893053

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Registry record

Entity type Individual (Type 1)

Name Dr. William C Holohan

Credential D.D.S.

Sex Male

Practice address 1220 Meadow Rd, Suite # 206, Northbrook, IL, 60062

Phone (847) 272-1588

Fax (847) 272-0581

Enumeration date Jan 8, 2007

Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

122300000X Dentist Dental Providers Primary

DDS · Doctor of Dental Surgery: A licensed dentist; DDS and DMD are equivalent dental degrees. About the DDS credential

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

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is William Holohan?

William Holohan is registered in NPPES with the primary taxonomy of Dentist. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.