Gives property, or parcel, ownership together with value information, which ensures fair assessment of Boston taxable and non-taxable property of all types and classifications. To preserve their integrity, the identifiers PID, CM_ID, GIS_ID, ZIPCODE, and MAIL_ZIPCODE all are marked with an underscore ("_") as the last character.

Year-specific documentation for the FY2008 through FY2013 files is not currently available, but the format of those files is equivalent to that described in the FY2014 documentation.

The Assessing Online application brings direct access for taxpayers, homeowners, real estate and legal professionals as well as business owners to property parcel data including assessed value, location, ownership and tax information for each piece of property in the city.

The information assists homeowners directly in their ownership responsibilities by providing the current value and tax status of their property. Professional real estate, business and legal entities access and draw upon Boston property parcel data to support and enhance their specific business operations. The GIS data appended to this application provides valuable graphical contexts for researchers, analysts and other professionals interested in demographical patterns, property usage and development.

To access parcel information:Enter an address or zoom in by using the +/- tools or your mouse scroll wheel. Parcels will draw when zoomed in.Click on a parcel to display a popup with information about that parcel.Click the "Basemap" button to display background aerial imagery.From the "Layers" button you can turn map features on and off.Complete Help (PDF)Parcel Legend:Full Map LegendAbout this ViewerThis viewer displays land property boundaries from assessor parcel maps across Massachusetts. Each parcel is linked to selected descriptive information from assessor databases. Data for all 351 cities and towns are the standardized "Level 3" tax parcels served by MassGIS. More details ...Read about and download parcel dataUpdatesV 1.1: Added 'Layers' tab. (2018)V 1.2: Reformatted popup to use HTML table for columns and made address larger. (Jan 2019)V 1.3: Added 'Download Parcel Data by City/Town' option to list of layers. This box is checked off by default but when activated a user can identify anywhere and download data for that entire city/town, except Boston. (March 14, 2019)V 1.4: Data for Boston is included in the "Level 3" standardized parcels layer. (August 10, 2020)V 1.4 MassGIS, EOTSS 2021