Onsite Physician Services of Illinois, S.C.

Primary specialty

Family Medicine PhysicianTaxonomy code 207Q00000X

Legal business name

ONSITE PHYSICIAN SERVICES OF ILLINOIS, S.C.

Practice address

16052 Industrial Pkwy
Middlefield, OH 44062-9382

Phone

(815) 363-9500

NPI assigned

Nov 11, 2025

Organization subpart

No

Registry information is reported by the provider to CMS and is not verified. About this source

Authorized official

Name

Dr. Alan Gegenheimer, DO

Title

President

Phone

(815) 363-9500

Specialties & licenses 1

Addresses

Locations

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1762819200000",
    "enumeration_type": "NPI-2",
    "last_updated_epoch": "1762819200000",
    "number": "1801766084",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "4805 PRIME PKWY",
            "city": "MCHENRY",
            "state": "IL",
            "postal_code": "600507002"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "16052 INDUSTRIAL PKWY",
            "city": "MIDDLEFIELD",
            "state": "OH",
            "postal_code": "440629382",
            "telephone_number": "815-363-9500"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "organization_name": "ONSITE PHYSICIAN SERVICES OF ILLINOIS, S.C.",
        "organizational_subpart": "NO",
        "enumeration_date": "2025-11-11",
        "last_updated": "2025-11-11",
        "certification_date": "2025-11-11",
        "status": "A",
        "authorized_official_last_name": "GEGENHEIMER",
        "authorized_official_first_name": "ALAN",
        "authorized_official_title_or_position": "PRESIDENT",
        "authorized_official_telephone_number": "815-363-9500",
        "authorized_official_name_prefix": "Dr.",
        "authorized_official_credential": "DO"
    },
    "taxonomies": [
        {
            "code": "207Q00000X",
            "taxonomy_group": "193200000X MULTI-SPECIALTY GROUP",
            "desc": "Family Medicine",
            "state": null,
            "license": null,
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

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• Family Medicine Physician in Middlefield, OH
• Providers in Middlefield, OH by specialty
• Family Medicine Physician in Ohio

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Nov 11, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.