Start with the Washington State Archives’ King County Assessor Real Property Record Cards title and match your documented parcel, house-and-street, or addition clue to Search This Title. A blank result means you should recheck the identifier and the collection’s access limits.
This is an assessment-card search. It is different from the County’s historical permit registers and application cards and from a recorded plat or agreement. Decide which record you need before interpreting a hit.
Translate the clue into the card form’s key
Work from a number or wording you can trace to a document already in hand. Save its original spelling alongside the search version. The archive’s title page gives three particularly useful conversions:
- Parcel number: use the first ten digits of the tax account, formatted as six digits–four digits. For a wholly fictional number,
654321098765becomes654321-0987. Keep the original identifier as well as the search version. - Street address: enter the house number separately; omit directions and street types from Street Name. Keep the full original address in your notes so you can rule out a similar street name.
- Plat or addition: use an abbreviated plat name or part of it, omitting “Addition.” Keep the original wording and any legal-description reference in your worksheet.
The form also names former-building, former-street, and former-address fields. Former-address entries can be incomplete, so use a documented old clue only where the card provides it. Avoid entering unrelated guesses in several fields at once: you want to know which documented clue led to a candidate card.
Check the record identity before using a card
Suppose an old document gives one parcel number, while later paperwork shows a changed street label. Copy both versions with their dates. Prepare each documented key in a separate row and link the input to its dated source. Note whether another document supplies an independent addition clue. The example shows the method only.
If a candidate appears, compare the card’s address, parcel and legal-description clues with the document that started the search. A matching house number alone is weak evidence where names or boundaries changed. Write down which fields agree, which conflict, and which are unreadable. Preserve a card’s own date or update notation rather than treating the date you found it online as the date of a building event.
Even a located card remains one record in a sequence. Compare its dated annotations and identifiers with the document that started the search rather than turning a structure description into an approval. A card does not mean that a permit was issued, work passed inspection, or occupancy was approved. If your question is a construction authorization, take the card’s identifiers to the permit-register guide as a separate step.
Treat a missing online image as an access question
The title describes a 1937–1940 survey, updates through 1972, and partial online scanning. Those are collection boundaries; an individual parcel may lack a digitized card for some years. The archive’s search help describes People, Keyword, and Detailed searches as separate modes. Use this title’s own fields for its documented clues; a broad keyword miss says little about this title.
For a missing card, preserve four lines: the dated document that supplied the clue; each input actually tried; the observed online response; and the particular card or era still needed. Mark a miss as “no online card identified,” which leaves room for an offline card. The title points to the Washington State Archives Puget Sound Regional Branch for archival research. Ask where that series can be checked beyond the scan.
Keep the subsequent record lane explicit. A notation that points to a recorded plat or agreement belongs in a recorded-map or instrument search; the assessor card only points to it. Conversely, that recorded-instrument guide uses its own parcel and date rules. Keep each system’s input format and any negative result with that system. Keep the card, permit, and recorded-document references on separate lines until an actual identifier connects them.
Washington State Archives collection and search-help pages checked October 5, 2026.