Mara Downing, MD
Mara Downing, MD is a provider specialising in Student in an Organized Health Care Education/Training Program in O Fallon, IL, registered under NPI 1003756461.
Getting there
Here is what surrounds this office in O Fallon, based on OpenStreetMap data collected Sep 26, 2026. Parking is available about 0.44 mi away. The nearest transit stop is 964 ft away, served by Green Mount at Misty Valley. A pharmacy sits 0.47 mi from the entrance (Walgreens), which helps if you leave with a prescription.
Getting here and what is nearby
Transit Cambridge at Green Mount 324 ft ~2 min
Transit Cambridge at Indian Creek 761 ft ~3 min
Parking 817 ft ~4 min
Transit Green Mount at Misty Valley 964 ft ~4 min
Parking 925 ft ~4 min
Pharmacy CVS Pharmacy 0.23 mi ~5 min
Hotel Hilton Garden Inn 0.33 mi ~7 min
Restaurant Lion's Choice 0.35 mi ~8 min
Restaurant First Watch 0.40 mi ~9 min
455 Regency Park, O'Fallon 62269
Mo-Su 07:00-14:30
Restaurant Bella Milano 0.41 mi ~9 min
Parking 0.44 mi ~9 min
Hotel TownePlace Suites 0.46 mi ~10 min
Convenience Circle K 0.47 mi ~10 min
Pharmacy Walgreens 0.47 mi ~10 min
Gas station Circle K 0.48 mi ~10 min
Hotel Extended Stay America 0.51 mi ~11 min
Distances are straight‑line estimates — walking routes may be longer. Hours and phone numbers can change; call ahead to confirm.
Credentials and Medicare
NPPES does not list a state licence number for this record. That is not unusual — organizations and some provider types are not required to file one. Verify current licensure with the relevant state board before care.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Student in an Organized Health Care Education/Training Program covers
An individual who is enrolled in an organized health care education/training program leading to a degree, certification, registration, and/or licensure to provide health care. NUCC Health Care Provider Taxonomy, code 390200000X
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1003756461 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 28, 2026 |
| Last updated | Mar 28, 2026 |
| Status | Active |
| Sole proprietor | No |
| Gender | Female |
| Credential | MD |
| Practice address |
3 SAINT ELIZABETH BLVD STE 4000 O Fallon, IL 62269 (618) 233-5480 Fax (184) 445-8791 |
| Other names |
Mara Keller Former Legal Business Name |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 0 | 0 | 3 | 7 | 5 | 6 | 4 | 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 0 | 0 | 3 | 5 | 5 | 3 | 4 | 3 |
Sum = 49 · next multiple of 10 = 50 · check digit = 1 · actual last digit = 1
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.