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

Mark Gronski, LPC

Clinical Social Worker in O Fallon, MO · enumerated 2012.

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

National Provider Identifier

1841565363

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Registry record

Entity type Individual (Type 1)
Name Mark Gronski
Credential LPC
Sex Male
Practice address O Fallon, MO, 63366
Phone (636) 281-1990
Fax (636) 281-1995
Enumeration date Mar 16, 2012
Last updated in NPPES Mar 16, 2012

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 2005000398 (MO) Primary
LPC · Licensed Professional Counselor: A licensed mental-health counselor providing psychotherapy. About the LPC 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

Where does Mark Gronski practice?
The practice location on file with NPPES is in O Fallon, MO. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Mark Gronski?
The National Provider Identifier (NPI) for Mark Gronski is 1841565363, a Type 1 (individual) record in the CMS NPPES registry.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2012-03-16.