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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

MARISSA THIRION
NPI 1023773413
Social Worker - Clinical in Seattle, WA

Active since November 01, 2021
4500 9TH AVE NE STE 300, SEATTLE, WA 98105(206) 608-8251 Get Directions Write a Review

NPPES record last updated: October 7, 2026. Verified against the NPPES registry weekly; last sync: October 11, 2026.

Record update history: Oct 7, 2026, Nov 1, 2021 (2 updates tracked since 2021).

About Marissa Thirion NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

MARISSA THIRION (NPI 1023773413) is an individual clinical provider in Seattle, Washington and active in the NPI registry since November 2021. She maintains a secondary practice location in Downey.

NPPES Registry Identity

NPI1023773413
Entity TypeIndividualFemale
Primary Taxonomy1041C0700X
Provider Legal NameMARISSA THIRION
Location Address4500 9TH AVE NE STE 300Seattle, WA 98105-4762
Mailing Address1532 24th Ave Apt BSeattle, WA 98122-3199 · (330) 998-4308
Phone(206) 608-8251
Sole ProprietorNo
Enumeration DateNovember 1, 2021
Last NPPES UpdateOctober 7, 20262 updates tracked since enumeration
NPPES CertifiedOctober 7, 2026
✔ NPI 1023773413 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtySocial Worker · ClinicalBehavioral Health & Social Service Providers
Taxonomy Code1041C0700X
Definition
A social worker who holds a master's or doctoral degree in social work from an accredited school of social work in addition to at least two years of post-master's supervised experience in a clinical setting. The social worker must be licensed, certified, or registered at the clinical level in the jurisdiction of practice. A clinical social worker provides direct services, including interventions focused on interpersonal interactions, intrapsychic dynamics, and life management issues. Clinical social work services are based on bio-psychosocial perspectives. Services consist of assessment, diagnosis, treatment (including psychotherapy and counseling), client-centered advocacy, consultation, evaluation, and prevention of mental illness, emotional, or behavioral disturbances.
Also ListedBehavior TechnicianTaxonomy 106S00000X
4500 9TH AVE NE STE 300, Seattle, WA 98105
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Secondary Practice Location 1

Location 112432 Bellflower BlvdDowney, CA 90242-2806 · Phone (818) 241-6780

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

MICHELE HALFHILL L.AC.
Acupuncturist
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 963-8978
MS. MARIE ELIZABETH LOEB MSW
Social Worker (Clinical)
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 234-6932
DR. SHIRLEY JUAN LEY PSYD
Psychologist
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 271-3608
SEPIDEH KITTLESON
Social Worker (Clinical)
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 234-6932
RUTH NEILSON M.A. PSYCHOLOGY
Counselor (Mental Health)
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 949-0381
MS. SHERRY TERESA THOMAS LMHC, SUDP
Counselor (Mental Health)
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 567-1973
TAYLOR NGUYEN
Social Worker (Clinical)
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 327-3111
LEA HUTCHINSON MCKINSTRY N.D.
Naturopath
4500 9TH AVE NE STE 300
SEATTLE, WA 98105
King County (206) 524-0863

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Marissa Thirion's NPI number?

The NPI number for Marissa Thirion is 1023773413. It was assigned to this individual provider in the NPPES registry on November 1, 2021.

Where is Marissa Thirion located?

Marissa Thirion practices at 4500 9th Ave NE Ste 300, Seattle, WA 98105. The listed phone number is (206) 608-8251.

What is Marissa Thirion's specialty?

The primary specialty registered for this NPI is Social Worker, specializing in Clinical, with taxonomy code 1041C0700X.

When was this NPI record last updated?

The NPPES record for Marissa Thirion was last updated on October 7, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.