Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mr. Mark W. Bontrager, MSW, LCSW

Clinical Social Worker in Napa, CA · enumerated 2007.

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

National Provider Identifier

1801946785

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Registry record

Entity type Individual (Type 1)

Name Mr. Mark W. Bontrager

Credential MSW, LCSW

Sex Male

Practice address 1801 Oak St, Napa, CA, 94559

Phone (707) 224-8266

Enumeration date Jan 11, 2007

Last updated in NPPES Sep 25, 2015

Taxonomy & licenses

1041C0700X Clinical Social Worker Behavioral Health & Social Service Providers · License 23579 (CA) Primary

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

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.

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Frequently asked questions

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is Mark Bontrager?

Mark Bontrager is registered in NPPES with the primary taxonomy of Clinical Social Worker. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Other providers at this practice address

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2015-09-25.