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.
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
- Kaleb Todd, DOGeneral Practice Physician1285499848
- Eric Toennies, DCChiropractor1952819971
- Lindsay Tolksdorf, D.O.Family Medicine Physician1992155741
- Julianne Tomac, DNP, FNP-CFamily Nurse Practitioner1245018944
- Charles Tompkins, LPCMental Health Counselor1215896519
- Tara Topper, FNP-CFamily Nurse Practitioner1649660200
- Theresa TownsendBehavior Analyst1285389908
- Kaitlin TrameSpeech-Language Pathologist1144115452
- Isaac Tran, M.D.Hospitalist Physician1154777597
- Deborah Treacy, M.D.Emergency Medicine Physician1558391524
- Dorrie Tredway, MDFamily Medicine Physician1891787040
- Amanda Trickel, BCBABehavior Analyst1427670306
- Zoe TriplettBehavior Technician1396592366
- Alexander TuckerBehavior Technician1740996073
- Ruth Turkson, MDStudent in an Organized Health Care Education/Training Program1962106732
- Michael Turner, LCPCProfessional Counselor1316707185
- Emma Tuttle, RBTBehavior Technician1568135317
- Dezmauri TylerBehavior Technician1063381358
- Randi Tyler, D.C.Chiropractor1740534320
- Christina Unangst, RBTBehavior Technician1578109336
- Lynn Underwood, MA, LCPCProfessional Counselor1700353679
- Scott Underwood, D.C.Chiropractor1508033960
- Hina Usman, MDFamily Medicine Physician1720575053
- Adaku Uzo-Okereke, M.D.Neurology Physician1497105704
- Taylor ValentineBehavior Analyst1952801615
- Amy Vallem, MSW, LCSWClinical Social Worker1659723591
- Marlon Van HamBehavior Analyst1053885749
- Michael Vanantwerp, MDEmergency Medicine Physician1790349033
- Nicole VandelindeProfessional Counselor1629683743
- Bethany VarelNurse Practitioner1538617402
- Mary Varel, CCC-SLPSpeech-Language Pathologist1366830424
- Claire Vargo, FNPNurse Practitioner1831712835
- Kareem VaughnProfessional Counselor1346097193
- Katelyn Venhaus, RBTBehavior Technician1841836608
- Seema VermaHospitalist Physician1326380908
- John Vick, DCChiropractor1235135617
- Larry Vick, D.C.Chiropractor1356358253
- Lillian Vincent, RBTBehavior Technician1265243372
- Elizabeth Vonderhaar, MDObstetrics & Gynecology Physician1770711947
- Brandy WagnerBehavior Technician1023668126
- Octavia Wagner, RBTBehavior Technician1427855170
- Roy Wagner, DOFamily Medicine Physician1477187383
- Sahej WaliaGeneral Practice Physician1891440780
- Jason Walker, D.C.Chiropractor1174599138
- Kelli WalkingtonPhysical Therapy Assistant1861188179
- Mark Walshauser, M.D.Hematology & Oncology Physician1306020664
- Cierra Walters, PT, DPTPhysical Therapist1538926456
- Sydney WaltersBehavior Technician1104708551
- Christine Walthes, APRN, FNP-CFamily Nurse Practitioner1982247342
- Katarina Waltman, RBTBehavior Technician1295371052
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.