Abstract: A delinquent payment portal system is described herein. The delinquent payment portal system can obtain transformed assessor and/or property tax data (e.g., assessor data and/or property tax data converted from one format to another format compatible with the delinquent payment portal system) from a parcel data store. The delinquent payment portal system can then use some or all of the retrieved data to generate user interface data that, when rendered by a user device, causes the user device to display a graphical user interface (GUI) depicting any of the data or features described herein, including property tax delinquency data details by land type, city, zip code, and/or other geographical area (e.g., county, state, etc.), property tax delinquency data map details, and/or property tax delinquency data year over year concurrently and/or overlapping within a single view.