Mark Williams, PH.D.
NPI 1801839204 · Clinical Neuropsychologist · Mount Pleasant, SC
Mark Williams, PH.D. is a Clinical Neuropsychologist provider in Mount Pleasant, SC (NPI 1801839204).
Provider details
- NPI number
- 1801839204
- Entity type
- Individual
- Primary specialty
- Clinical NeuropsychologistBehavioral Health & Social Service Providers
- Credential
- PH.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 994 (SC)
Specialties & taxonomies
Behavioral Health & Social Service Providers
Behavioral Health & Social Service Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-06-14
- Last updated
- 2025-09-11
Frequently asked questions
- What is Mark Williams's NPI number?
- Mark Williams's National Provider Identifier (NPI) is 1801839204, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Williams's specialty?
- Mark Williams is listed in the NPPES registry with a primary specialty of Clinical Neuropsychologist (Behavioral Health & Social Service Providers).
- Where is Mark Williams located?
- Mark Williams's practice location on file with NPPES is 886 Johnnie Dodds Blvd, Mount Pleasant, SC 29464-3190.
- What is Mark Williams's phone number?
- The practice phone number listed in the NPPES registry for Mark Williams is (843) 425-7142.
- Is Mark Williams's NPI active?
- Yes — Mark Williams's NPI (1801839204) is active in the NPPES registry as of the last update on 2025-09-11.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.