Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Dr. Mark R Northfield, MD

Individual provider Orthopaedic Surgery Physician · NPI 1861406316

Dr. Mark R Northfield, MD is an Orthopedic Surgery in Petaluma, California. Graduated from Warren Alpert Medical School of Brown University in 1991, 35 years ago. Practices with Providence Medical Foundation, a 1,465-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
35
Trained at
Warren Alpert Medical School of Brown University
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

1496 Professional Dr Ste 601
Petaluma, CA 94954
Phone: (707) 778-1131
Fax: (707) 778-3818
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Orthopaedic Surgery Physician (primary) Taxonomy 207X00000X · Licence G77114 (CA)

Record details

NPI number1861406316
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedJuly 28, 2006
Last updated in NPPESNovember 9, 2021
Certification dateNovember 9, 2021

Medicare enrollment

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

Medicare specialtyORTHOPEDIC SURGERY
Medical schoolWARREN ALPERT MEDICAL SCHOOL OF BROWN UNIVERSITY
Graduated 1991 (35 years in practice)
Group practice Providence Medical Foundation — 1465 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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