Free parcel data in Massachusetts

Yes. Massachusetts publishes a free statewide parcel layer: Massachusetts Property Tax Parcels (MassGIS Level 3), from MassGIS (Commonwealth of Massachusetts Bureau of Geographic Information). Coverage: All 351 cities and towns (351 distinct TOWN_ID values). It's a public ArcGIS REST service with no API key or login.

The layer

Layer	Massachusetts Property Tax Parcels (MassGIS Level 3)
Publisher	MassGIS (Commonwealth of Massachusetts Bureau of Geographic Information)
Coverage	All 351 cities and towns (351 distinct TOWN_ID values)
Data vintage	Assessor FY2018-FY2027 depending on town; layer edited 2026
Terms	Public; attribution: MassGIS (Bureau of Geographic Information)
Fields	parcel number (MAP_PAR_ID, LOC_ID, PROP_ID); site address (SITE_ADDR); owner (OWNER1); deed reference
Not published	plat references
REST endpoint	`https://services1.arcgis.com/hGdibHYSPO59RG1h/arcgis/rest/services/Massachusetts_Property_Tax_Parcels/FeatureServer/0`
Last verified	2026-10-19 with a live point and parcel-number query

Notes for GIS users

MAP_PAR_ID is only unique within a town; combine with TOWN_ID (MassGIS numeric town id) or CITY. LOC_ID is statewide-unique. Condo/multi-record parcels can return more than one polygon (POLY_TYPE).

How to use it

QGIS: Layer > Data Source Manager > ArcGIS REST Server, add a connection with the service URL (the endpoint above without the final /0), then add the layer. Filter to your area before exporting.
ArcGIS Pro: Add Data > Data From Path, paste the endpoint.
Direct query: append /query?geometry=LON,LAT&geometryType=esriGeometryPoint&inSR=4326&spatialRel=esriSpatialRelIntersects&outFields=*&f=geojson to get the parcel at a point.
CAD: see getting a parcel into AutoCAD or Civil 3D.

Assessor parcel lines are for taxation and are often 5 to 50 ft off the legal boundary. Why.

Basesheet uses this to draw the parcel line on a base plan for any Massachusetts address, with LiDAR contours, soils, flood zones and wetlands.

Build a base plan