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MyDec Data Files

MyDec data files include the information from every recorded Real Estate Transfer Declaration submitted through the Illinois Department of Revenue’s (IDOR) online MyDec system. As of June 2025, the MyDec data files have been migrated to the Illinois Open Data portal at data.illinois.gov. The data sets contain all records from 2013 to present and are updated weekly. Data sets on this portal can be filtered, and can be downloaded, either in full or after being filtered, in various file formats. If you wish to duplicate the old file format, export as a Tab-Separated Values file. 

The data sets can be accessed by entering “Property Tax” on the “Search for Data” tab of the Illinois Open Data portal.

The data sets include the following:  

and may also include:

  • PTAX-203-A, Illinois Real Estate Transfer Declaration Supplemental Form A – This form is filed with the PTAX-203 if
    • On Form PTAX-203, Line 11 the sale price is over $1 million, and
    • On Form PTAX-203, Line 8 the property’s current use is marked “Apartment building (over 6 units),” “Office,” “Retail establishment,” “Commercial building,” “Industrial building,” or “Other.”
  • PTAX-203-B, Illinois Real Estate Transfer Declaration Supplemental Form B – This form is filed with the PTAX-203 if the transfer of beneficial interest in real property was made without using a deed or a trust document.
  • Additional Buyers – If there are multiple buyers listed in Step 4 of the Form PTAX-203, they are included in this data table.
  • Additional Sellers – If there are multiple sellers listed in Step 4 of the Form PTAX-203, they are included in this data table.
  • Additional PIN data – If there are multiple PINs on Line 3 of the Form PTAX-203, they are included in this data table.
  • Personal Property Data – If personal property was included as a part of the sale on Line 12a of the Form PTAX-203, it is included in this data table.

The Layout / File Format link explains the layout of the information presented.

Note: Private and personal information has been excluded from the data pursuant to the Illinois Freedom of Information Act. The accuracy of any declaration recorded through MyDec has not been verified by IDOR and does not include the prior year’s assessment information.

MyDec at MyTax Illinois allows users to search for Illinois Real Estate Transfer Declarations (Forms PTAX-203, PTAX 203-A, PTAX 203-B), as well as Cook County and City of Chicago Real Estate Transfer Declarations, if applicable, without logging in to a MyDec account. Visit the MyDec at MyTax Illinois website to perform a search.