NPPES file of Aug 9, 2026

Doctors and health care providers in O Fallon, IL

1,077 individual NPPES records list a practice address in O Fallon, 44th of 541 Illinois cities. The largest group is behavior technician: 295, 27% of the city's records, against 4% across Illinois. Page 20 of 22.

CMS NPPES registry, file of Aug 9, 2026 · method · Verify with CMS →

The 8 largest groups in O Fallon

Source: CMS NPPES primary taxonomy, file of Aug 9, 2026.

O Fallon in Illinois

  • Rank in Illinois44th of 541 cities by records
  • Share of the state0.4% of Illinois's records
  • Specialties present25 or more taxonomy codes
  • Top three groups37.7% of all records
  • Behavior Technician rank4th of the 10 Illinois cities with the most

Compared with Illinois as a whole, O Fallon has 7× the state's share of behavior technician records and 0.25× its share of mental health counselor records.

Providers in O Fallon, alphabetically

  1. Kaleb Todd, DOGeneral Practice Physician1285499848
  2. Eric Toennies, DCChiropractor1952819971
  3. Lindsay Tolksdorf, D.O.Family Medicine Physician1992155741
  4. Julianne Tomac, DNP, FNP-CFamily Nurse Practitioner1245018944
  5. Charles Tompkins, LPCMental Health Counselor1215896519
  6. Tara Topper, FNP-CFamily Nurse Practitioner1649660200
  7. Theresa TownsendBehavior Analyst1285389908
  8. Kaitlin TrameSpeech-Language Pathologist1144115452
  9. Isaac Tran, M.D.Hospitalist Physician1154777597
  10. Deborah Treacy, M.D.Emergency Medicine Physician1558391524
  11. Dorrie Tredway, MDFamily Medicine Physician1891787040
  12. Amanda Trickel, BCBABehavior Analyst1427670306
  13. Zoe TriplettBehavior Technician1396592366
  14. Alexander TuckerBehavior Technician1740996073
  15. Ruth Turkson, MDStudent in an Organized Health Care Education/Training Program1962106732
  16. Michael Turner, LCPCProfessional Counselor1316707185
  17. Emma Tuttle, RBTBehavior Technician1568135317
  18. Dezmauri TylerBehavior Technician1063381358
  19. Randi Tyler, D.C.Chiropractor1740534320
  20. Christina Unangst, RBTBehavior Technician1578109336
  21. Lynn Underwood, MA, LCPCProfessional Counselor1700353679
  22. Scott Underwood, D.C.Chiropractor1508033960
  23. Hina Usman, MDFamily Medicine Physician1720575053
  24. Adaku Uzo-Okereke, M.D.Neurology Physician1497105704
  25. Taylor ValentineBehavior Analyst1952801615
  26. Amy Vallem, MSW, LCSWClinical Social Worker1659723591
  27. Marlon Van HamBehavior Analyst1053885749
  28. Michael Vanantwerp, MDEmergency Medicine Physician1790349033
  29. Nicole VandelindeProfessional Counselor1629683743
  30. Bethany VarelNurse Practitioner1538617402
  31. Mary Varel, CCC-SLPSpeech-Language Pathologist1366830424
  32. Claire Vargo, FNPNurse Practitioner1831712835
  33. Kareem VaughnProfessional Counselor1346097193
  34. Katelyn Venhaus, RBTBehavior Technician1841836608
  35. Seema VermaHospitalist Physician1326380908
  36. John Vick, DCChiropractor1235135617
  37. Larry Vick, D.C.Chiropractor1356358253
  38. Lillian Vincent, RBTBehavior Technician1265243372
  39. Elizabeth Vonderhaar, MDObstetrics & Gynecology Physician1770711947
  40. Brandy WagnerBehavior Technician1023668126
  41. Octavia Wagner, RBTBehavior Technician1427855170
  42. Roy Wagner, DOFamily Medicine Physician1477187383
  43. Sahej WaliaGeneral Practice Physician1891440780
  44. Jason Walker, D.C.Chiropractor1174599138
  45. Kelli WalkingtonPhysical Therapy Assistant1861188179
  46. Mark Walshauser, M.D.Hematology & Oncology Physician1306020664
  47. Cierra Walters, PT, DPTPhysical Therapist1538926456
  48. Sydney WaltersBehavior Technician1104708551
  49. Christine Walthes, APRN, FNP-CFamily Nurse Practitioner1982247342
  50. Katarina Waltman, RBTBehavior Technician1295371052

The largest Illinois cities

  1. Chicago63,379
  2. Springfield4,997
  3. Naperville4,634
  4. Peoria4,621
  5. Evanston4,013

All of Illinois →

How to read this directory

O Fallon, Illinois appears in the CMS National Plan and Provider Enumeration System with 1,077 registered healthcare providers spanning 25 or more distinct NUCC-taxonomy specialties. This count includes every individual clinician who has applied for an NPI and listed a practice address in O Fallon - physicians, dentists, nurse practitioners, physician assistants, chiropractors, physical therapists, optometrists, psychologists, podiatrists, and every other credentialed provider type CMS tracks. It does not measure hospital beds, urgent-care capacity, or whether a given clinic is accepting new patients; it measures the pool of professionals with current NPI enrollment and a O Fallon practice location on file. Every figure is drawn from the federal National Provider Identifier Registry (CMS NPPES) - more than 7 million providers, maintained since May 2007, with 2024 Medicare Part D data, and, according to CMS, can be searched, compared, and traced in our methodology.

The provider mix in O Fallon is weighted toward Behavior Technician (295 clinicians, followed by Speech-Language Pathologist with 67 and Family Medicine Physician with 44). That distribution reflects how NPPES records specialty: providers self-select a primary taxonomy code, so a family physician who also practices geriatrics will show up under whichever NUCC code they registered first. Relative to Illinois's population, O Fallon reports roughly 8.6 providers per 100,000 residents using the state-level denominator, which is a rough proxy rather than a precise access-to-care measurement; the true catchment area of any {cityName} clinician extends beyond the municipal boundary.

Of Illinois's most common specialties, Internal Medicine Physician is the most prominent one with no provider currently listing a O Fallon practice address, a coverage gap O Fallon patients typically fill by traveling to a larger nearby hub.

For O Fallon patients, this directory is most useful as a starting shortlist. Important: PlainDoctor is a directory of publicly available CMS government data, not a review site, a ranking, or medical advice. NPPES data is self-reported and refreshed monthly; call the practice directly to confirm the provider is still there, accepts your insurance, and is taking new patients.

For informational purposes only; this directory is not medical advice and not a substitute for checking a license. See also: how to find a doctor and how to verify one.

Common questions

How many doctors are in O Fallon, IL?

There are 1,077 registered healthcare providers in O Fallon, IL, covering 25 or more specialties. This includes physicians, dentists, therapists, and other licensed providers.

What are the most common medical specialties in O Fallon?

The most common specialties in O Fallon are Behavior Technician, Speech-Language Pathologist, Family Medicine Physician, Student in an Organized Health Care Education/Training Program, Behavior Analyst. Behavior Technician has the most providers with 295.

Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov). Records are self-reported registrations, not licenses.

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.