The Cook County Clerk’s Office has provided important information regarding the USPS Postmark changes and how that may affect vote by mail ballots. Effective January 1, 2026, the US Postal Service (USPS) changed how postmarks are defined. Previously, mail was postmarked the day you dropped it in the mailbox. Now the mail will be postmarked the day it is processed at the post office, which can sometimes be days later. In order to make sure your vote counts for the 3/17/26 election and beyond, go to the post office counter to drop off your vote by mail ballot and request a hand-stamped postmark. https://www.cookcountyclerk.com/USPS-Locations OR, beginning March 2, you may drop your mail ballot at any of the 55 drop-box locations throughout suburban Cook County. https://cookcountyclerk.com/MBdropbox
Cook County Vote by Mail Changes Info for 3/17/26 Election Flyer