Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

William Dean Billows, PHD HSPP

Clinical Psychologist in Mount Prospect, IL · enumerated 2005.

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

National Provider Identifier

1619969854

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Registry record

Entity type Individual (Type 1)

Name William Dean Billows

Credential PHD HSPP

Sex Male

Practice address Mount Prospect, IL, 60056

Phone (847) 909-9858

Fax (847) 299-4952

Enumeration date Aug 15, 2005

Last updated in NPPES Jul 21, 2022

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

103TC0700X Clinical Psychologist Behavioral Health & Social Service Providers · License 071.006777 (IL) Primary

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

What specialty is William Billows?

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

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.

Other providers at this practice address

Browse all →

Mark D Parisi Psy D & Associates PC Clinical Psychologist · Mount Prospect, IL NPI 1487728283 Mark D. Parisi, Psy.D., P.C. Mental Health Clinic/Center (Including Community Mental Health Center) · Mount Prospect, IL NPI 1376730028 Allison Desantis Professional Counselor · Mt Prospect, IL NPI 1609233469 Nupur Sharma Professional Counselor · Mount Prospect, IL NPI 1396299160 Lindy Vandersteeg Mental Health Counselor · Mount Prospect, IL NPI 1740719855 Helena Griglione Health Information Specialist/Technologist · Mt Prospect, IL NPI 1437663887

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2022-07-21.