Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

William M Mills, MD

Individual provider Emergency Medicine Physician · NPI 1497779300

William M Mills, MD practises Emergency Medicine in Walnut Creek, California. Graduated from Baylor College of Medicine in 1993, 33 years ago. Practices with Cep America - California, a 1,267-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
33
Trained at
Baylor College of Medicine
Licensed in
CA
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

1601 Ygnacio Valley Rd
Walnut Creek, CA 94598-3122 Not confirmed with CMS for 19 years — call before visiting
Phone: (925) 939-3000
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Emergency Medicine Physician (primary) Taxonomy 207P00000X · Licence A62432 (CA)

Record details

NPI number1497779300
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJuly 26, 2006
Last updated in NPPESOctober 26, 2007

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyEMERGENCY MEDICINE
Medical schoolBAYLOR COLLEGE OF MEDICINE
Graduated 1993 (33 years in practice)
Group practice Cep America - California — 1267 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations5 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients426
Services billed 518 a service is one billed item, such as a visit, a test or a procedure
Average patient age77

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

  • John Muir Medical Center - Concord Campus Hospital · Concord, CA · listed as John Muir Medical Ctr Concord Campus
  • Eastern Plumas Hospital - Portola Campus Hospital · Portola, CA
  • John Muir Medical Center - Walnut Creek Campus Hospital · Walnut Creek, CA

Colleagues at Cep America - California

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1267 clinicians in the practice; 12 are shown here.

Other providers in Walnut Creek