Active NPI
Mark L. Collister, L.S.W.
- Social Worker
- Williamsport, PA
National Provider Identifier
1225078082
On this page
Key facts
NPPES NPI Registry- Primary specialty
- Social Worker
- License
- SW124379
- Practice address
- 435 W 4TH St
Williamsport, PA 17701-6001 - Phone
- (570) 322-7873
- Fax
- (570) 322-8026
- NPI assigned
- Jun 8, 2006
- Sex
- Male
- Sole proprietor
- No
NPPES NPI Registry
Registry information is reported by the provider to CMS and is not verified. About this source
Specialties & licenses 1
| Specialty (taxonomy) | Code | License | State | Primary |
|---|---|---|---|---|
| Social Worker | 104100000X | SW124379 | PA | Primary |
Addresses
Primary practice location
435 W 4TH St
Williamsport, PA 17701-6001
Mailing address
10 Catherine Dr
Williamsport, PA 17701-1292
Phone (570) 322-7873
Medicare participation
Medicare enrollment files- Medicare fee-for-service enrollment
- Not listed in the public Medicare enrollment file
National Provider Directory
National Provider Directory- Medicare enrollment (NPD)
- Not enrolled
State licenses
| License | State | Type | Specialty |
|---|---|---|---|
| SW124379 | PA | MD | Social Worker |
NPI Registry JSON
The complete NPPES record for this NPI in the NPI Registry API format.
{
"created_epoch": "1149724800000",
"enumeration_type": "NPI-1",
"last_updated_epoch": "1783900800000",
"number": "1225078082",
"addresses": [
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "MAILING",
"address_type": "DOM",
"address_1": "10 CATHERINE DR",
"city": "WILLIAMSPORT",
"state": "PA",
"postal_code": "177011292",
"telephone_number": "570-322-7873",
"fax_number": "570-322-8026"
},
{
"country_code": "US",
"country_name": "United States",
"address_purpose": "LOCATION",
"address_type": "DOM",
"address_1": "435 W 4TH ST",
"city": "WILLIAMSPORT",
"state": "PA",
"postal_code": "177016001",
"telephone_number": "570-322-7873",
"fax_number": "570-322-8026"
}
],
"practiceLocations": [],
"basic": {
"last_name": "COLLISTER",
"first_name": "MARK",
"middle_name": "L.",
"credential": "L.S.W.",
"sole_proprietor": "NO",
"sex": "M",
"enumeration_date": "2006-06-08",
"last_updated": "2026-07-13",
"status": "A"
},
"taxonomies": [
{
"code": "104100000X",
"taxonomy_group": "",
"desc": "Social Worker",
"state": "PA",
"license": "SW124379",
"primary": true
}
],
"identifiers": [],
"endpoints": [],
"other_names": []
}Other providers in Williamsport, PA
Sources for this page
- NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Jul 13, 2026; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
- National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.