Provider Profile
Mark G. Willoughby
Unclaimed ProfileAbout Mark Willoughby
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Specialty
Credentials & Licensing
License numbers are what the provider reported to NPPES when the NPI was issued or updated. NPPES does not verify licensure; confirm current standing with the state licensing board.
Contact Information
- (626) 453-3400
- Email not available
Practice Locations
3430 COGSWELL RD
El Monte, CA 91732
Related providers
Connections drawn from the registry and from what providers have told us. A link here is not a referral or an endorsement.
Other addiction & substance abuse counselors at this location 8
Same specialty, same street address — most likely the same department or group.
Also at this address 4
Providers at the same street address. Each files their own registry entry, so a shared practice often appears under several different names.
Common questions
What is Mark G. Willoughby's specialty?
Mark G. Willoughby is an addiction & substance abuse counselor in El Monte, CA. That is the designation recorded for this NPI in the federal registry.
NPI registry
Where can I find Mark G. Willoughby?
Mark G. Willoughby is listed at 3430 Cogswell Rd, El Monte, CA 91732. Addresses come from the NPI registry and can lag a move, so confirm before travelling.
NPI registry
How do I contact Mark G. Willoughby?
The number on file is (626) 453-3400. Guide.md cannot book appointments or pass on messages — please call the office directly.
NPI registry
What is Mark G. Willoughby's NPI number?
Mark G. Willoughby's National Provider Identifier is 1174038756. It is issued by the Centers for Medicare & Medicaid Services and is unique and permanent — it does not change if they move practice.
NPI registry
How long has Mark G. Willoughby been practicing?
Mark G. Willoughby has 9+ years experience. Registered with an NPI since 2017. National Provider Identifiers only began in 2005, so a provider who qualified earlier may have practiced for longer than this.
NPI registry
Has Mark G. Willoughby confirmed this information?
Not yet. This profile is built from public federal data and has not been confirmed by Mark G. Willoughby. If this is you, claiming it is free.
Guide.md
Provider data sourced from the NPPES NPI Registry and CMS public datasets. Information is provided for reference and is not medical advice.