Free parcel data in Wisconsin

Yes. Wisconsin publishes a free statewide parcel layer: Wisconsin Statewide Parcel Map Database (V12), from Wisconsin State Cartographer's Office / Wisconsin Land Information Program, Dept. of Administration. Coverage: All 72 counties (3,574,646 parcels). It's a public ArcGIS REST service with no API key or login.

The layer

Layer	Wisconsin Statewide Parcel Map Database (V12)
Publisher	Wisconsin State Cartographer's Office / Wisconsin Land Information Program, Dept. of Administration
Coverage	All 72 counties (3,574,646 parcels)
Data vintage	V12 (2026 release); TAXROLLYEAR mostly 2025, updated annually
Terms	Public; attribution: Wisconsin Statewide Parcel Map Database Project (V12), State Cartographer's Office / WLIP at DOA
Fields	parcel number (PARCELID, TAXPARCELID, STATEID); site address (SITEADRESS); owner (OWNERNME1)
Not published	deed references, plat references
REST endpoint	`https://services3.arcgis.com/n6uYoouQZW75n5WI/arcgis/rest/services/Wisconsin_Statewide_Parcels_DB/FeatureServer/0`
Last verified	2026-10-19 with a live point and parcel-number query

Notes for GIS users

CONAME is uppercase county name (e.g. 'DANE', 'ST CROIX'); PARCELFIPS holds the 3-digit county FIPS. PLACENAME is the municipality ('CITY OF MADISON'). STATEID = county FIPS + PARCELID. TAXPARCELID is often null. One stray CONAME value 'MENOMONIE' exists alongside 'MENOMINEE'.

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 Wisconsin address, with LiDAR contours, soils, flood zones and wetlands.

Build a base plan