Quick answers
- Which hospitals does William Kopelman work at?
- Medicare's official clinician data lists William Kopelman at 1 hospital: Mad River Community Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does William Kopelman see patients?
- Medicare's clinician data lists 1 practice location in Sun Valley, CA. Call before your visit to confirm the address.
- What is William Kopelman's specialty?
- Medicare lists General Practice as the primary specialty, and also Emergency Medicine.
- Does William Kopelman accept Medicare assignment?
- Yes. Medicare's clinician data says William Kopelman accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for William Kopelman?
- (866) 247-3141, as listed in official Medicare / NPI Registry data.
- What is William Kopelman's NPI number?
- 1457318164. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where William Kopelman works
Medicare's Facility Affiliation Data lists William Kopelman at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Mad River Community HospitalArcata, CA · Acute Care Hospital · CCN 050028
Practice locations
Addresses where William Kopelman is enrolled with Medicare (CMS data updated 2026-10-02).
- 9449 San Fernando RdSun Valley, CA 91352 (866) 247‑3141
Group practices
Medicare enrollment lists William Kopelman as a member of this group (CMS data updated 2026-10-02).
- Erx Plus Professional Corporation3 clinicians in the group
Specialties
- General Practiceprimary
- Emergency Medicinealso
Other general practitioners in California
Clinicians with the same Medicare primary specialty in California — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Brody School Of Medicine At East Carolina University |
| Graduation year | 1996 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1457318164 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians