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

Individual provider Emergency Medicine Physician · NPI 1780818377

Mary-Stewart Willsie, DO practises Emergency Medicine in Newark, Delaware. Graduated from Kansas City University of Physicians and Surgeons in 2009, 17 years ago. Practices with Main Line Healthcare, a 1,153-clinician group and accepts Medicare assignment. Licensed in Delaware.

Years since qualifying
17
Trained at
Kansas City University of Physicians and Surgeons
Licensed in
DE
In the registry since
2009
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

4755 Ogletown Stanton Rd
Newark, DE 19718-0001 Not confirmed with CMS for 13 years — call before visiting
Phone: (130) 273-3100
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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 C7-0004280 (DE)

Record details

NPI number1780818377
Entity typeIndividual (Type 1)
GenderFemale
Credentials DO
Sole proprietorYes
NPI enumeratedMay 11, 2009
Last updated in NPPESJuly 25, 2013

Medicare enrollment

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

Medicare specialtyEMERGENCY MEDICINE
Medical schoolKANSAS CITY UNIVERSITY OF PHYSICIANS AND SURGEONS
Graduated 2009 (17 years in practice)
Group practice Main Line Healthcare — 1153 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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 patients376
Services billed 714 a service is one billed item, such as a visit, a test or a procedure
Average patient age74

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.

Colleagues at Main Line Healthcare

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1153 clinicians in the practice; 12 are shown here.

Other providers in Newark