Land records · Parcel maps · October 7, 2026
What Is a Tax Map Key (TMK)? Hawaii Parcel IDs
What is a tax map key? Hawaii's TMK parcel number identifies each property by county, zone, section, plat, and parcel. How to read and look one up.
What is a tax map key? A tax map key, or TMK, is the parcel identification number used in Hawaii. It is a structured code that points to a specific parcel on the state’s tax maps, organized by county or island, zone, section, plat, and parcel. TMKs appear on deeds, tax bills, permits, and planning documents, and they are the main way to search property records in Hawaii. Condominium units often add a further number to identify the individual unit within the parcel. This page is general land-records background, not legal advice.
Reading a TMK
A typical TMK might be written as (1) 2-3-004:005. The parts are:
| Part | Meaning |
|---|---|
| (1) | County or island division |
| 2 | Zone |
| 3 | Section |
| 004 | Plat |
| 005 | Parcel |
Formats differ in punctuation, and some systems write it as a continuous string with leading zeros, such as 123004005. Condominium units may add a four-digit unit or CPR number at the end.
County codes
The first digit generally identifies the county: 1 for Honolulu (Oahu), 2 for Maui County, 3 for Hawaii County (Big Island), and 4 for Kauai. Check local conventions, since some systems use different prefixes.
Where TMKs appear
- Real property tax bills and assessments.
- Recorded deeds at the Bureau of Conveyances or Land Court.
- Building permits and zoning applications.
- County GIS maps.
How to look up a TMK
County real property tax websites allow searches by address, owner, or TMK. GIS viewers show parcels with their TMKs on the map. See how to use a county GIS viewer and how to find a parcel number.
TMK and tax maps
TMKs refer to plats in the state’s tax map system. Each plat sheet shows parcels with their numbers, dimensions, and sometimes easements. See what is a tax map sheet.
Changes to TMKs
When land is subdivided or consolidated, new TMKs are assigned. Old TMKs may be retired, so older documents might reference numbers that no longer exist. Research should trace parent and child parcels. See do parcel numbers change.
Land Court vs regular system
Hawaii has two recording systems: the regular system and Land Court, a Torrens-style registration. TMKs identify parcels in both, but document references differ.
Condominiums
A condominium project usually sits on one TMK, and each unit is distinguished by an added number. Tax bills are issued per unit.
Example
A buyer looking at a house on Oahu finds the TMK (1) 4-5-012:031 on the listing. The (1) is the City and County of Honolulu. Zone 4, section 5, and plat 012 point to a specific tax map sheet, and parcel 031 is the lot on that sheet. Searching the county real property site by that TMK brings up the assessment, the owner of record, and the tax history. Entering it in the county GIS viewer shows the parcel boundary and nearby easements.
Using TMKs in research
When ordering title reports, applying for permits, or requesting records, give the full TMK including the county prefix and any condo unit number. Older documents may use different punctuation or omit leading zeros, so try several formats when searching.
Bottom line
A tax map key, or TMK, is Hawaii’s parcel number, built from county, zone, section, plat, and parcel numbers, with extra digits for condo units. It is used on deeds, tax bills, permits, and GIS maps. Search county property tax sites or GIS by address or TMK. Explore parcel maps via the Platbookmapper map.
What is a tax map key FAQ
What is a TMK number?
Hawaii’s parcel identification number.
How do I find my TMK?
Check your tax bill, deed, or county property search.
What does the first digit of a TMK mean?
It usually identifies the county or island.
Do condos have their own TMK?
Units usually add a number to the project’s TMK.
Can a TMK change?
Yes, after subdivision or consolidation.