Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mary Ann Williams

Social Worker in Festus, MO · enumerated 2007.

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

National Provider Identifier

1205968146

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Registry record

Entity type Individual (Type 1)

Name Mary Ann Williams

Sex Female

Practice address 227 E Main St, Festus, MO, 63028

Phone (636) 931-2700

Fax (636) 931-5304

Enumeration date Mar 9, 2007

Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

104100000X Social Worker Behavioral Health & Social Service Providers Primary

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

What specialty is Mary Ann Williams?

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

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.

Other providers at this practice address

Browse all →

Compass Health, Inc Mental Health Clinic/Center (Including Community Mental Health Center) · Festus, MO NPI 1598781189 Margaret Pigg Professional Counselor · Festus, MO NPI 1164585535 Joan Ellis Clinical Social Worker · Festus, MO NPI 1750444196 Sandra Mueller Professional Counselor · Festus, MO NPI 1427111889 Diana Ridgon Professional Counselor · Festus, MO NPI 1487717849 Susan Cassimatis Professional Counselor · Festus, MO NPI 1598829004 Ronald Beach Psychiatry Physician · Festus, MO NPI 1205990579 Louise Brotherton Registered Nurse · Festus, MO NPI 1427186154

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.