Type 2 · Organization ✓ Active NPI ✓ Valid NPI checksum

East River Psychological Services

Clinical Psychologist in Mitchell, SD · enumerated 2022 · authorized official Matthew Christiansen, Clinical Psychologist/Owner.

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

National Provider Identifier

1598487308

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Registry record

Entity type Organization (Type 2)

Legal business name East River Psychological Services

Practice address 3413 N Ohlman St, Mitchell, SD, 57301

Phone (605) 999-0728

Enumeration date Sep 19, 2022

Last updated in NPPES Sep 6, 2024

Taxonomy & classification

103TC0700X Clinical Psychologist Behavioral Health & Social Service Providers Primary

Authorized official

Name Matthew Christiansen

Title Clinical Psychologist/Owner

Phone (605) 630-7387

Other identifiers

Identifier	Type	State	Issuer
1639136088	Medicaid	SD	-

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

Where is East River Psychological Services located?

The practice location on file with NPPES is in Mitchell, SD.

How current is this record?

Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2024-09-06. Verify at npiregistry.cms.hhs.gov.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-09-06.