Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

MS. Margaret Mary Grossmayer, APRN, FNP-C

Individual provider Nurse Practitioner · NPI 1548140973

MS. Margaret Mary Grossmayer, APRN, FNP-C is a Nurse Practitioner in St Charles, Illinois. Qualified in 2025, 1 year ago. Practices with Midwest Express Care 2, Inc, a 219-clinician group and accepts Medicare assignment. Licensed in Illinois.

Years since qualifying
1
Licensed in
IL
In the registry since
2025
What do these letters mean?
APRN — Advanced Practice Registered Nurse
The umbrella licence covering nurse practitioners, midwives, anaesthetists and clinical nurse specialists.
FNP-C — Family Nurse Practitioner, Certified
A family nurse practitioner certified by the AANP.

See every abbreviation used in this directory →

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Practice location Address checks out

3310 W Main St Ste 100
St Charles, IL 60175-1024
Phone: (630) 377-2800
Fax: (630) 377-6774
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Nurse Practitioner (primary) Taxonomy 363L00000X · Licence 209-033129 (IL)

Record details

NPI number1548140973
Entity typeIndividual (Type 1)
GenderFemale
Credentials APRN , FNP-C
Sole proprietorNo
NPI enumeratedSeptember 5, 2025
Last updated in NPPESSeptember 21, 2026
Certification dateSeptember 21, 2026

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyNURSE PRACTITIONER
Medical schoolOTHER
Graduated 2025 (1 years in practice)
Group practice Midwest Express Care 2, Inc — 219 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Colleagues at Midwest Express Care 2, Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 219 clinicians in the practice; 12 are shown here.

Other providers in St Charles