Quick answers
- Does Mariann S. Williams accept Medicare assignment?
- Yes. Medicare's clinician data says Mariann S. Williams accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- What is Mariann S. Williams's NPI number?
- 1922166776. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Mariann S. Williams works
Medicare's Facility Affiliation Data lists Mariann S. Williams at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- North Valley HospitalTonasket, WA · Critical Access Hospital · Emergency services: listed by Medicare · CCN 501321
Practice locations
Addresses where Mariann S. Williams is enrolled with Medicare (CMS data updated October 2, 2026).
- 118 N Whitcomb AveTonasket, WA 98855 (509) 486‑3191
- 203 S Western AveTonasket, WA 98855 (509) 486‑2151
Group practices
Medicare enrollment lists Mariann S. Williams as a member of this group (CMS data updated October 2, 2026).
- Okanogan County Public Hospital Dist No 442 clinicians in the group
Specialties
- Nurse Practitionerprimary
Other nurse practitioners in Tonasket
Clinicians with the same Medicare primary specialty in Tonasket, WA — not a recommendation.
Other clinicians in Okanogan County Public Hospital Dist No 4
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | NP |
|---|---|
| Graduation year | 1994 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1922166776 |
| 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 October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- 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