Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Mark G Kiefner PHD LLC

Organization Clinical Psychologist · NPI 1528539335

Mark G Kiefner PHD LLC is a Clinical Psychologist in Portland, Maine. Registered with an NPI since 2018.

In the registry since
2018
What do these letters mean?
LLC — Limited liability company
A form of business registration, not a clinical qualification.

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Practice location Address checks out

225 Commercial St Ste 403
Portland, ME 04101-6603
Phone: (207) 400-2694
Fax: (207) 331-3249
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Clinical Psychologist (primary) Taxonomy 103TC0700X

Record details

NPI number1528539335
Entity typeOrganization (Type 2)
Organization subpartNo
Authorized official Mark Kiefner — Owner · (207) 400-2694
NPI enumeratedDecember 6, 2018
Last updated in NPPESDecember 6, 2018
Mailing address98 Sheridan St, Portland, ME 04101-2626

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