John Stewart Ensign, PHD

John Stewart Ensign is a Clinical Psychologist provider (Psychologist) practicing in Davis, CA, registered in the NPPES registry with NPI 1669573143 since 2006. The credential PHD stands for Doctor of Philosophy.

✓ Active NPI ✓ Valid NPI checksum Sole proprietor

NPI	1669573143
Entity type	Individual (Type 1)
Name	John Stewart Ensign
Credential	PHD
Sex	Male
Practice address	Davis, CA, 95616
Phone	5303040711
Fax	5302972609
Enumeration date	2006-09-26
Last updated in NPPES	2022-07-26

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

Taxonomy & licenses

Taxonomy code	Specialty	Primary	License	State
103TC0700X	Clinical Psychologist	Primary	PSY14539	CA

PHD — Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD credential

Copy-ready billing details

Provider: John Ensign, PHD
NPI: 1669573143
Taxonomy: 103TC0700X (Clinical Psychologist)
Address: Davis, CA, 95616

Other providers at this practice address

NPI	Name	Type	Specialty	Location
1225103062	Helen Krell	Individual	Child & Adolescent Psychiatry Physician	Davis, CA
1003062225	Mitchel Adler	Individual	Psychologist	Davis, CA
1639409725	Diana Hirning-Johnson	Individual	Marriage & Family Therapist	Davis, CA
1255662490	Hali Rowen	Individual	Clinical Psychologist	Davis, CA

Verify this record

Cross-check NPI 1669573143 against the authoritative CMS record: view John Stewart Ensign on the official NPPES registry .

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 or validate an NPI number.

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 John Ensign?

John Ensign 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.

Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2022-07-26.