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

MS. Margaret Koster, LCSW

Individual provider Psychologist · NPI 1770609919

MS. Margaret Koster, LCSW is a Psychologist in Willits, California. Practices as a sole proprietor. Licensed in California.

Licensed in
CA
In the registry since
2007
Specialties on file
2
What do these letters mean?
LCSW — Licensed Clinical Social Worker
A social worker licensed to diagnose and treat mental health conditions independently.

See every abbreviation used in this directory →

Practice location Address checks out

16100 N Highway 101 Spc 72
Willits, CA 95490-9715
Phone: (707) 459-5970
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Psychologist (primary) Taxonomy 103T00000X · Licence LCS5820 (CA)
Clinical Social Worker Taxonomy 1041C0700X · Licence LCS5820 (CA)

Record details

NPI number1770609919
Entity typeIndividual (Type 1)
GenderFemale
Credentials LCSW
Sole proprietorYes
NPI enumeratedMarch 21, 2007
Last updated in NPPESSeptember 11, 2025