Quick answers
- Where does Holly Hammack see patients?
- Medicare's clinician data lists 1 practice location in Upland, CA. Call before your visit to confirm the address.
- What is Holly Hammack's specialty?
- Medicare lists Clinical Social Worker as the primary specialty.
- Does Holly Hammack accept Medicare assignment?
- Medicare's clinician data says Holly Hammack may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- Does Holly Hammack offer telehealth?
- Medicare's clinician data says Holly Hammack offers telehealth services. Ask the office which visits can be done by video or phone.
- What is the phone number for Holly Hammack?
- (909) 931-3388, as listed in official Medicare / NPI Registry data.
- What is Holly Hammack's NPI number?
- 1295939338. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where Holly Hammack is enrolled with Medicare (CMS data updated 2026-10-02).
- 585 N Mountain Ave, Suite BUpland, CA 91786 (909) 931‑3388
Group practices
Medicare enrollment lists Holly Hammack as a member of this group (CMS data updated 2026-10-02).
- Mountain View Behavioral Health Inc5 clinicians in the group
Specialties
- Clinical Social Workerprimary
Other clinical social workers in Upland
Clinicians with the same Medicare primary specialty in Upland, CA — not a recommendation.
Clinician information
| Credential | CSW |
|---|---|
| Graduation year | 1980 |
| Gender (as listed) | Female |
| Medicare assignment | May accept for some services |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1295939338 |
| 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
- 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