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

Dr. Gregory Mark Gerrish, MD

Individual provider Surgery Physician · NPI 1992097703

Dr. Gregory Mark Gerrish, MD practises General Surgery in Watertown, South Dakota. Graduated from Sanford School of Medicine of University of South Dakota in 2011, 15 years ago. Practices with Prairie Lakes Health Care System Inc, a 112-clinician group and accepts Medicare assignment. Licensed in South Dakota.

Years since qualifying
15
Trained at
Sanford School of Medicine of University of South Dakota
Licensed in
SD
In the registry since
2011
Specialties on file
2
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

401 9th Ave NW Prairie Lakes Hospital
Watertown, SD 57201-1623 Not confirmed with CMS for 10 years — call before visiting
Phone: (605) 882-7000
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Surgery Physician (primary) Taxonomy 208600000X · Licence 10080 (SD)
Student in an Organized Health Care Education/Training Program Taxonomy 390200000X

Record details

NPI number1992097703
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedMay 12, 2011
Last updated in NPPESAugust 17, 2016

Medicare enrollment

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

Medicare specialtyGENERAL SURGERY
Medical schoolSANFORD SCHOOL OF MEDICINE OF UNIVERSITY OF SOUTH DAKOTA
Graduated 2011 (15 years in practice)
Group practice Prairie Lakes Health Care System Inc — 112 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Upper gastrointestinal (GI) endoscopy for acid reflux 92 times · 75th percentile
Colonoscopy 80 times · 74th percentile
Hernia repair (minimally invasive) 1–10 times
Hernia repair - groin (open) 1–10 times
Removal of tissue 1–10 times
Removal or shaving of skin growth 1–10 times

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

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 patients296
Services billed 644 a service is one billed item, such as a visit, a test or a procedure
Average patient age72

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.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $268 9 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Prairie Lakes Health Care System Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 112 clinicians in the practice; 12 are shown here.

Other providers in Watertown