Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

Big Sky Internal Medicine

Q: What is the NPI number for Big Sky Internal Medicine?

The NPI for Big Sky Internal Medicine is 1023100732, a Type 2 (organization) record in the CMS NPPES registry.

Internal Medicine Physician in Lewistown, MT · enumerated 2006 · authorized official Janet Grensten, Office Manager.

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

National Provider Identifier

1023100732

Verified

See something wrong? Report a correction

Registry record

Entity type Organization (Type 2)

Legal business name Big Sky Internal Medicine

Practice address 310 Wendell Ave Ste 101, Lewistown, MT, 59457

Phone (406) 535-1490

Fax (406) 535-1491

Enumeration date Sep 29, 2006

Last updated in NPPES Oct 20, 2009

Taxonomy & classification

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians Primary

Authorized official

Name Janet Grensten

Title Office Manager

Phone (406) 535-1490

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 is the NPI number for Big Sky Internal Medicine?

The NPI for Big Sky Internal Medicine is 1023100732, a Type 2 (organization) record in the CMS NPPES registry.

Who is the authorized official for Big Sky Internal Medicine?

NPPES lists Janet Grensten (Office Manager) as the authorized official for this organization.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2009-10-20.