Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Ms. Claire Siverson, LCSW

Social Worker in Vallejo, CA · enumerated 2007.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1598974255

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name Ms. Claire Siverson

Credential LCSW

Sex Female

Practice address Vallejo, CA, 94590

Phone (707) 558-6730

Enumeration date May 21, 2007

Last updated in NPPES Jul 13, 2023

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

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 18079 (CA) Secondary

104100000X Social Worker Behavioral Health & Social Service Providers · License LCS18079 (CA) Primary

LCSW · Licensed Clinical Social Worker: A social worker licensed for clinical practice including mental-health therapy. About the LCSW credential

Other identifiers

Identifier	Type	State	Issuer
11707262	Other	CA	CAQH PROVIDER ID
295224	Other	CA	MHN

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 → Validate an NPI →

Frequently asked questions

Where does Claire Siverson practice?

The practice location on file with NPPES is in Vallejo, CA. Providers can have multiple locations; NPPES lists the primary practice address.

What is the NPI number for Claire Siverson?

The National Provider Identifier (NPI) for Claire Siverson is 1598974255, a Type 1 (individual) record in the CMS NPPES registry.

Other providers at this practice address

Browse all →

Barbara Cornell Marriage & Family Therapist · Vallejo, CA NPI 1598892606 Annette Glass Marriage & Family Therapist · Vallejo, CA NPI 1265565972 Judith Faye Marriage & Family Therapist · Vallejo, CA NPI 1386869352 Jendayi Ford Clinical Social Worker · Vallejo, CA NPI 1710184262 Timothy Tarbill Mental Health Counselor · Vallejo, CA NPI 1477701241 Ginny Matchette Marriage & Family Therapist · Vallejo, CA NPI 1497900666 Derek Krauss Marriage & Family Therapist · Vallejo, CA NPI 1144513755 Sarah Pierce Clinical Social Worker · Vallejo, CA NPI 1417236738

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2023-07-13.