NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Mark Eric Terwilliger, CPNP

Pediatric Nurse Practitioner in Harker Heights, TX · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1386607992

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)
Name Mark Eric Terwilliger
Credential CPNP
Sex Male
Practice address Harker Heights, TX, 76548
Phone (877) 800-5722
Fax (254) 698-1673
Enumeration date Apr 7, 2006
Last updated in NPPES May 5, 2014

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

363LP0200X Pediatric Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 854069 (TX) Primary

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What specialty is Mark Terwilliger?
Mark Terwilliger is registered in NPPES with the primary taxonomy of Pediatric Nurse Practitioner. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2014-05-05.