Free parcel data in Hawaii

Yes. Hawaii publishes a free statewide parcel layer: Parcels - Hawaii Statewide (Statewide TMKs), from Hawaii Statewide GIS Program (Office of Planning and Sustainable Development). Coverage: All 4 counties (Hawaii, Honolulu, Kauai, Maui). It's a public ArcGIS REST service with no API key or login.

The layer

Layer	Parcels - Hawaii Statewide (Statewide TMKs)
Publisher	Hawaii Statewide GIS Program (Office of Planning and Sustainable Development)
Coverage	All 4 counties (Hawaii, Honolulu, Kauai, Maui)
Data vintage	May 2026 (county sources dated Apr-May 2026)
Terms	Public; attribution: Counties of Hawaii, Honolulu, Kauai and Maui; Hawaii Statewide GIS Program
Fields	parcel number (tmk_txt, cty_tmk, tmk)
Not published	owner names, deed references, plat references
REST endpoint	`https://geodata.hawaii.gov/arcgis/rest/services/ParcelsZoning/MapServer/25`
Last verified	2026-10-19 with a live point and parcel-number query

Notes for GIS users

tmk_txt is the 9-digit TMK with leading island/division digit (division+zone+section+plat3+parcel3, e.g. 324024105); cty_tmk drops the division digit (8 digits); tmk is numeric. County 12-digit TMKs append 4 CPR digits (qpub_link KeyValue). No situs address or owner fields. Point on a street returns 0 features.

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

Build a base plan