Coverage
What's Missing
2,145 counties have no published parcel dataset. Bountied counties are listed first — those pay a multiplied credit award, and filling one publishes it free for everybody.
Why a county ends up on this list
Usually because the county does not publish its parcel layer at all, or publishes it only as a paid product, or only as a map viewer with no download. A few are here because the file exists but has never passed verification — a snapshot that cannot be shown to be what it claims is not published, however inconvenient that is.
Every one of these is fillable by someone who already holds the data. The upload runs containment, schema and vintage checks before anything is published, so contributing is not a matter of being trusted; it is a matter of the file being what it says it is.