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 8 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. Khalila Guzman, PAMedical Physician Assistant1265919526
  2. Christopher HaasPediatric Dentistry1932782703
  3. Matthew Haas, PT, DPTPhysical Therapist1760236731
  4. Peyton Haas, RBTBehavior Technician1811752116
  5. Brynn Hackney, ATC, LATAthletic Trainer1184114878
  6. Timothy Hackney, D.C.Chiropractor1851458251
  7. Todd Hackney, D.C.Chiropractor1871681106
  8. Tahnee Hagenbuch, OTR/LPediatric Occupational Therapist1568708584
  9. Jacquelyn Hall-Davis, M.D.Child & Adolescent Psychiatry Physician1619042124
  10. Abigail Haloftis, B.S.Behavior Technician1871110163
  11. Keri Halwachs, RBTBehavior Technician1316583313
  12. Whitney Hames, BS, RDNRegistered Dietitian1902722531
  13. David Hamilton, M.S. CCC-SLPSpeech-Language Pathologist1386882108
  14. Kara HamiltonSpeech-Language Pathologist1831318385
  15. Owen Hamilton, MD, MPHSFamily Medicine Physician1750961181
  16. Daniel Hammond, RBTBehavior Technician1356101422
  17. Joseph HammondBehavior Technician1831914167
  18. Ashley HanfelderBehavior Analyst1235611153
  19. Christina Hardin-WeissSpeech-Language Pathologist1104396084
  20. Cynthia Hardin-Weiss, PTPhysical Therapist1447561196
  21. Makyla Hargrave, RBTBehavior Technician1336800838
  22. Brittney HarperFamily Nurse Practitioner1780501726
  23. Allison Harris, PA-CPhysician Assistant1790588739
  24. Courtney Harris, CRNACertified Registered Nurse Anesthetist1235764218
  25. Hayley HarrisBehavior Analyst1467033043
  26. Rebecca HarrisFamily Nurse Practitioner1669022182
  27. Teresa HarrisLicensed Practical Nurse1164801197
  28. Patresa Harris-WilliamsPrimary Care Nurse Practitioner1407459522
  29. Richard HarrisonPharmacist1639288376
  30. Jamie Hart, CRNACertified Registered Nurse Anesthetist1477090322
  31. Natalie HartSpeech-Language Pathologist1801768171
  32. James Harting, LCSWClinical Social Worker1932337409
  33. Alexa HartmannBehavior Technician1588493597
  34. Michelle Hartrich, DCChiropractor1376593400
  35. Angela Harvey, CRNACertified Registered Nurse Anesthetist1588707020
  36. Nataly HatfieldMental Health Counselor1013807304
  37. James Havens, PHARMDPharmacist1962211862
  38. Lori Hawkins, NPNurse Practitioner1760267736
  39. Emilijah HaysBehavior Technician1619826013
  40. Samuel Haywood, MDUrology Physician1427357698
  41. Jamie HeatonBehavior Technician1285430827
  42. Shaelin Heiman, PA-CPhysician Assistant1336832880
  43. Lauren HeimbuecherSpeech-Language Pathologist1003446758
  44. Steve Heitkamp, DMIN, LCPCProfessional Counselor1609867712
  45. Madonna HeldenbrandBehavior Technician1386130565
  46. Lori Beth Helmers, APRNAdult Health Nurse Practitioner1063457794
  47. Grace HendersonBehavior Technician1639888514
  48. Nell Hennon, D.O.Family Medicine Physician1992739221
  49. Jaclyn HerbstreitBehavior Analyst1174023253
  50. Kristine Hettenhausen, OTR/LOccupational Therapist1750520060

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.