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.
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
- Khalila Guzman, PAMedical Physician Assistant1265919526
- Christopher HaasPediatric Dentistry1932782703
- Matthew Haas, PT, DPTPhysical Therapist1760236731
- Peyton Haas, RBTBehavior Technician1811752116
- Brynn Hackney, ATC, LATAthletic Trainer1184114878
- Timothy Hackney, D.C.Chiropractor1851458251
- Todd Hackney, D.C.Chiropractor1871681106
- Tahnee Hagenbuch, OTR/LPediatric Occupational Therapist1568708584
- Jacquelyn Hall-Davis, M.D.Child & Adolescent Psychiatry Physician1619042124
- Abigail Haloftis, B.S.Behavior Technician1871110163
- Keri Halwachs, RBTBehavior Technician1316583313
- Whitney Hames, BS, RDNRegistered Dietitian1902722531
- David Hamilton, M.S. CCC-SLPSpeech-Language Pathologist1386882108
- Kara HamiltonSpeech-Language Pathologist1831318385
- Owen Hamilton, MD, MPHSFamily Medicine Physician1750961181
- Daniel Hammond, RBTBehavior Technician1356101422
- Joseph HammondBehavior Technician1831914167
- Ashley HanfelderBehavior Analyst1235611153
- Christina Hardin-WeissSpeech-Language Pathologist1104396084
- Cynthia Hardin-Weiss, PTPhysical Therapist1447561196
- Makyla Hargrave, RBTBehavior Technician1336800838
- Brittney HarperFamily Nurse Practitioner1780501726
- Allison Harris, PA-CPhysician Assistant1790588739
- Courtney Harris, CRNACertified Registered Nurse Anesthetist1235764218
- Hayley HarrisBehavior Analyst1467033043
- Rebecca HarrisFamily Nurse Practitioner1669022182
- Teresa HarrisLicensed Practical Nurse1164801197
- Patresa Harris-WilliamsPrimary Care Nurse Practitioner1407459522
- Richard HarrisonPharmacist1639288376
- Jamie Hart, CRNACertified Registered Nurse Anesthetist1477090322
- Natalie HartSpeech-Language Pathologist1801768171
- James Harting, LCSWClinical Social Worker1932337409
- Alexa HartmannBehavior Technician1588493597
- Michelle Hartrich, DCChiropractor1376593400
- Angela Harvey, CRNACertified Registered Nurse Anesthetist1588707020
- Nataly HatfieldMental Health Counselor1013807304
- James Havens, PHARMDPharmacist1962211862
- Lori Hawkins, NPNurse Practitioner1760267736
- Emilijah HaysBehavior Technician1619826013
- Samuel Haywood, MDUrology Physician1427357698
- Jamie HeatonBehavior Technician1285430827
- Shaelin Heiman, PA-CPhysician Assistant1336832880
- Lauren HeimbuecherSpeech-Language Pathologist1003446758
- Steve Heitkamp, DMIN, LCPCProfessional Counselor1609867712
- Madonna HeldenbrandBehavior Technician1386130565
- Lori Beth Helmers, APRNAdult Health Nurse Practitioner1063457794
- Grace HendersonBehavior Technician1639888514
- Nell Hennon, D.O.Family Medicine Physician1992739221
- Jaclyn HerbstreitBehavior Analyst1174023253
- Kristine Hettenhausen, OTR/LOccupational Therapist1750520060
The largest Illinois cities
- Chicago63,379
- Springfield4,997
- Naperville4,634
- Peoria4,621
- Evanston4,013
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.