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Maxwell Sumkin Butler, MD

Family Medicine Physician in Sun Prairie, WI · enumerated 2022 · practices at University of Wisconsin Medical Foundation Inc.

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

National Provider Identifier

1326787755

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Registry record

Entity type Individual (Type 1)
Name Maxwell Sumkin Butler
Credential MD
Sex Male
Practice address 2651 Windsor St, Sun Prairie, WI, 53590
Phone (608) 837-2206
Enumeration date Jun 2, 2022
Last updated in NPPES Aug 7, 2026

Taxonomy & licenses

207Q00000X Family Medicine Physician Allopathic & Osteopathic Physicians · License 85401 (WI) Primary
2084A0401X Addiction Medicine (Psychiatry & Neurology) Physician Allopathic & Osteopathic Physicians · License 85401-20 (WI) Secondary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD 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 Maxwell Butler?
Maxwell Butler is registered in NPPES with the primary taxonomy of Family Medicine Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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