Mark L. Day, M.D.
Internal Medicine Physician · Staunton, IL
Mark L. Day, M.D. is an internal medicine physician with a practice address in Staunton, Illinois, and NPI 1174679237, issued on Jan 25, 2007. Check the license (Illinois 036.117437, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- Mark L. Day
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 036.117437 IL
Self-reported in NPPES; status is on the state search - Practice location
- 400 N Caldwell St, Staunton, IL 62088
- Phone
- (618) 635-2200
- Enumerated
- Jan 25, 2007
- Record last updated
- Sep 29, 2020 (not updated in 6 years: call before relying on the address or phone)
- Fax
- (618) 635-3400
- Entity
- Type 1 · individual
Also registered at 400 N Caldwell St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Mallory BagaglioSpeech-Language Pathologist1932026986
- Michael Coalson, L.P.TPhysical Therapist1730247263
- Walter McDonald, C.R.N.A.Certified Registered Nurse Anesthetist1073685731
- Nicolas Pineda, M.D.Surgery Physician1639191000
Verify Mark L. Day in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 036.117437Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
98% fewer Medicare Part D claims than the average internal medicine physician in 2024
68 Medicare Part D claims for 22 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.
Most prescribed
- Azithromycin15 claims
- Prednisone12 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
3 internal medicine physician records list a practice address in Staunton
They are 3 of the 37 NPPES records with a practice address in Staunton, and 7,238 internal medicine physician records in Illinois.
All 3 in Staunton → All 7,238 in Illinois → Every provider in Staunton →
Other internal medicine physician records in Illinois
- Peter Abadeer, D.O.Bloomington, IL1760469522
- Motaz Abas, MDPeoria, IL1215510201
- Elias Abate, M.D.Chicago, IL1336712199
- Maliha Abbas, D.O.Chicago, IL1174963920
- Zareena Abbas, MDChicago, IL1427078872
- Abu Abbasi, MDChicago, IL1083243877
- Ayesha Abbasi, MDChicago, IL1376216705
- Khalda Abbasi, MDNaperville, IL1487705240
- Elmer Abbo, MDBurr Ridge, IL1710048541
- Paul Abbo, M.D.River Forest, IL1083693378
Common questions
What is Mark L. Day, M.D.'s NPI number?
Mark L. Day, M.D.'s National Provider Identifier (NPI) is 1174679237, issued on Jan 25, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Mark L. Day, M.D. located?
The NPPES record lists a practice address at 400 N Caldwell St, Staunton, IL, 62088. Phone: (618) 635-2200. Providers update this record themselves, so call before visiting.
How can I verify Mark L. Day, M.D.'s license?
NPPES lists Illinois license number 036.117437, as entered by the provider. Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Mark L. Day, M.D. prescribe under Medicare Part D?
In 2024, Mark L. Day, M.D. had 68 Medicare Part D claims for 22 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.