The 2024 Second Installment Property Tax Bill, released to property owners on November 14, 2025, by Cook County, included an error in the taxing district breakout on some (but not all) property tax bills, which has caused confusion for some residents.

The line items for “Village of Mt Prospect Library Fund” and “County of Cook” are displayed incorrectly on some tax bills. Specifically, the Mount Prospect Public Library’s 2023 tax amount has been incorrectly included within the amount shown for Cook County. As a result, the bill appears to show a 100% increase in Library taxes and a 68% decrease for Cook County, both of which are inaccurate.

The 2024 tax amounts are correct. The issue affects only the “2023 Tax” and “Difference” columns.

As of the morning of November 17, we do not have a statement from the Cook County Treasurer’s Office regarding this error or whether they intend to issue corrected bills. The library will share additional information when it becomes available.

If you want to see how much your property was taxed in 2023 for the Mount Prospect Public Library, you can compare last year’s property tax bill from the Cook County Property Tax Portal at: https://www.cookcountypropertyinfo.com/. Some residents will see that on the 2023 tax bill the library’s portion is listed correctly, where on the 2024 tax bill it is listed as $0. Similarly, on the “County of Cook” line you will see a significant discrepancy between 2023 and 2024. The most recent five years of the library’s audits, budgets, and levies are available here: https://mppldev.org/about-us/transparency/.