Contact the Cook County Assessor's office in Chicago, Illinois, by calling 312-443-7550, by mail or by online form. Business hours are 8:30 a.m. to 5:00 p.m., Monday through Friday. Contact information is available online at CookCountyAssessor.com, as of 2015.
The mailing address for the Cook County Assessor's office is 118 North Clark Street,Third Floor Room #320
Chicago, IL 60602. Visitors can email the office by navigating to its website and clicking Contact Our Offices at the bottom of the homepage. The online form prompts users to enter first name, last name, address and other information, and gives the option to receive a response by mail or email.