MARY HOWLAND WILLIAMSON MD
NPI 1770102014
Obstetrics & Gynecology in Freedom, CA
About Mary Howland Williamson Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARY HOWLAND WILLIAMSON MD (NPI 1770102014) is an individual obstetrics & gynecology provider in Freedom, California, licensed in California (A206967) and active in the NPI registry since April 2020. She is enrolled in Medicare PECOS, is affiliated with Hospital Of Univ Of Pennsylvania, and maintains a secondary practice location in Santa Cruz.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Location 1
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Mary Howland Williamson Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignment
Medicare enrollment records show Mary Williamson reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Trenton, NJ 08638
- Reassigned Medicare billing, New Jersey and Pennsylvania enrollments
- 581 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Hospital Affiliations CMS Care Compare 3
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Hospital Of Univ Of Pennsylvania
Acute Care Hospitals · Philadelphia, PADoylestown Hospital
Acute Care Hospitals · Doylestown, PASt Mary Medical Center
Acute Care Hospitals · Langhorne, PAPhysician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 95019 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Other Providers at the Same Location NPPES 18
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
FREEDOM, CA 95019
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Mary Williamson's NPI number?
The NPI number for Mary Williamson is 1770102014. It was assigned to this individual provider in the NPPES registry on April 15, 2020.
Where is Mary Williamson located?
Mary Williamson practices at 160 Green Valley Rd, Freedom, CA 95019. The listed phone number is (831) 458-5865.
What is Mary Williamson's specialty?
The primary specialty registered for this NPI is Obstetrics & Gynecology with taxonomy code 207V00000X.
Is Mary Williamson enrolled in Medicare?
Yes. Mary Williamson is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organization bills Medicare for Mary Williamson's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mary Williamson reassigns Medicare benefits to Capital Health Medical Group (Trenton, NJ). The reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Mary Williamson's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Mary Williamson accept?
Health plans from Ambetter Health, Ambetter Health of Delaware and Oscar Health list Mary Williamson as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Mary Williamson affiliated with any hospitals?
According to CMS data, Mary Williamson is affiliated with Hospital Of Univ Of Pennsylvania, Doylestown Hospital and St Mary Medical Center.
When was this NPI record last updated?
The NPPES record for Mary Williamson was last updated on October 9, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 29 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Mary Howland Williamson, MD · NPI 1770102014
Obstetrics & Gynecology physician in Freedom, California. Individual provider, active in the CMS NPPES registry since April 15, 2020.
## Identity
- **NPI:** 1770102014 (Entity type: Individual)
- **Enumerated:** April 15, 2020
- **Primary specialty:** Obstetrics & Gynecology · taxonomy 207V00000X
- **State license:** A206967 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 160 GREEN VALLEY RD, Freedom, CA 95019-3160
- **Phone:** (831) 458-5865
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Capital Health Medical Group (NPI 1437516887, Trenton, NJ), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2020
## Record status
- **NPPES last updated:** October 9, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1770102014) · Data from the CMS NPPES public registry.