U.S. Real Estate Transactions and Assessments from 1996

The Zillow Transaction and Assessment Database (ZTRAX) contains over 400 million public records across more than 2,750 U.S. counties. It includes deed transfers, mortgages, foreclosures, and property characteristics for approximately 150 million parcels. The dataset is sourced from a third-party provider and supplemented by Zillow's County Direct program, with temporal coverage varying by county but generally sufficient from April 1996 onward.

Use Cases

• Analyze deed transfer and mortgage patterns across 2,750+ counties to study regional housing market cycles.
• Model property valuations using historical assessment data and property characteristics for approximately 150 million parcels.
• Study foreclosure and tax delinquency rates over a 20+ year period for commercial and residential properties.
• Examine geographic information and prior valuations to assess property tax assessment equity.

Strengths

• Contains over 400 million detailed public records, making it one of the largest real estate databases.
• Covers approximately 150 million parcels across 3,100+ U.S. counties.
• Includes more than 20 years of temporal data for deed transfers, mortgages, and foreclosures.
• Data is supplemented by Zillow's County Direct program to address coverage gaps from third-party sources.

Limitations

• Temporal coverage varies greatly by county, with some areas having records only from the mid-2000s.
• The dataset contains known coverage gaps inherited from the original third-party data provider.
• The data files are very large, requiring researchers to plan for downloading specific geographic subsets.

Provenance

Source

Zillow, via a major third-party provider and its County Direct program.

Collection Method

Sourced from county assessor and recorder offices, supplemented by Zillow's internal County Direct initiative.

Time Range

Varies by county, with sufficient sample sizes for most areas from April 1996 onward.

Freshness

Updated approximately twice per year.

Geography

United States, covering 2,750+ counties for transactions and 3,100+ counties for parcel characteristics.