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

Mountainside Westchester LLC

Organization Case Management Agency · NPI 1457015331

Mountainside Westchester LLC is a Case Management Agency in New York, New York. Registered with an NPI since 2021.

In the registry since
2021
Specialties on file
2
What do these letters mean?
LLC — Limited liability company
A form of business registration, not a clinical qualification.

See every abbreviation used in this directory →

Claim this listing Report a problem Suggest an edit

Practice location Address checks out

243 W 18th St
New York, NY 10011-4569
Phone: (860) 362-5232
Fax: (877) 861-6507
Show map & directions

Directions in Google Maps · Apple Maps · OpenStreetMap

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

Specialties & licences

Community/Behavioral Health Agency (primary) Taxonomy 251S00000X
Case Management Agency Taxonomy 251B00000X

Record details

NPI number1457015331
Entity typeOrganization (Type 2)
Organization subpartNo
Authorized official Michelle Williamson — Director · (860) 362-5232
Other names Mountainside - Chelsea
NPI enumeratedOctober 26, 2021
Last updated in NPPESMarch 25, 2022
Certification dateMarch 25, 2022
Mailing addressPo Box 717, Canaan, CT 06018-0717

Other providers in New York