Data Sources & Coverage

This table is generated live from the same database that serves every page on the site: right now that is 90,690,166 parcel records across 1,968 county datasets in 46 states. All records originate as county assessor and GIS exports; how they are validated and processed is described on the methodology page.

How to read this table

Counties on file counts the county datasets currently published — a state with fewer counties here than it has in reality means the missing counties have not delivered usable data, not that their land is unrecorded. Newest load is when the most recent county dataset for that state finished loading into this site. Rolls from the last 2 years counts counties whose underlying assessor roll — the county’s own file date, which can be much older than our load date — falls within the last two years. Every county page carries its own roll date, because a 2018 roll answers questions about 2018.

Why some counties are missing

A county is absent for one of three reasons: it has not delivered data; its delivery failed validation — a county name the Census does not recognise, geometry of the wrong kind, files that describe a different county than their label claims; or its delivery was superseded by a better one that has not loaded yet. We publish a county when its data survives those checks, and not before. We would rather show a gap than fill one with records we cannot stand behind.