What is a TMK?
A TMK — Tax Map Key — is the unique ID for every parcel of land in Hawaiʻi. It's how the counties, title companies, lenders, and permitting agencies all reference a specific piece of ground: not by address, but by a short string like 1-2-3-016-044. Learn to read it and you can pull a parcel's entire public record. Here's exactly what each part means.
Five parts, in order.
The standard State of Hawaiʻi TMK is nine digits, written island-zone-section-plat-parcel. Take 1-2-3-016-044, an Oʻahu key:
1 – 2 – 3 – 016 – 044
You'll see the same key written several ways — with dashes (1-2-3-016-044), with a colon before the parcel (1-2-3-016:044), or as one run of digits (123016044). They're identical; the plat and parcel are just padded with leading zeros to three digits each. The first digit is always the island.
Which island?
That leading digit tells you the island and the county that assesses it. KILO reads parcels in all four counties — every island.
| First digit | Island | County / assessor |
|---|---|---|
| 1 | Oʻahu | City & County of Honolulu |
| 2 | Maui, Molokaʻi, Lānaʻi | County of Maui |
| 3 | Hawaiʻi (the Big Island) | County of Hawaiʻi |
| 4 | Kauaʻi, Niʻihau | County of Kauaʻi |
How to look up a TMK.
The fastest way is your county's real-property tax site: search by address and read the Tax Map Key (sometimes labeled Parcel Number) on the result. The same number is printed on your deed and your annual property-tax bill, and every parcel statewide is searchable on the Hawaiʻi Statewide GIS parcel viewer. Vacant land has no address but always has a TMK — which is exactly why diligence runs on the key, not the street.
The TMK is the key to the record.
Because every agency files by TMK, the number is the single handle that pulls a parcel's whole public footprint together — its zoning and land-use feasibility, flood zone, shoreline setback, wastewater and water service, and its cultural-resource context under HRS §6E. That's what KILO does: enter any Hawaiʻi TMK (or an address, and we resolve the TMK) and get a cited, parcel-level read across all of it — before you commit to the deal or the permit.
TMK FAQ.
Sources: TMK format and island codes per the Hawaiʻi Statewide GIS Program and the Hawaiʻi Department of Health "What is my TMK" guide. KILO is a pre-development screening tool, not a county system of record; confirm any official TMK with your county assessor.
Have a TMK in mind?
Tell us the parcel or the kind of deals you're screening across Hawaiʻi — access is invite-only during beta, and the more concrete the parcel, the more useful the first read.