Mark Williams
NPI 1215522602 · Addiction (Substance Use Disorder) Counselor · Chicago, IL
Mark Williams is a Addiction (Substance Use Disorder) Counselor provider in Chicago, IL (NPI 1215522602).
Provider details
- NPI number
- 1215522602
- Entity type
- Individual
- Primary specialty
- Addiction (Substance Use Disorder) CounselorBehavioral Health & Social Service Providers
- Sex
- Male
- Sole proprietor
- No
- License
- 26701 (IL)
Specialties & taxonomies
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
5 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
- 2021-03-08
- Last updated
- 2021-03-08
- Certified
- 2021-02-16
Frequently asked questions
- What is Mark Williams's NPI number?
- Mark Williams's National Provider Identifier (NPI) is 1215522602, 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 Addiction (Substance Use Disorder) Counselor (Behavioral Health & Social Service Providers).
- Where is Mark Williams located?
- Mark Williams's practice location on file with NPPES is 200 W Monroe St Ste 1150, Chicago, IL 60606-5036.
- What is Mark Williams's phone number?
- The practice phone number listed in the NPPES registry for Mark Williams is (314) 369-8849.
- Is Mark Williams's NPI active?
- Yes — Mark Williams's NPI (1215522602) is active in the NPPES registry as of the last update on 2021-03-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.