The original application deadline was Wednesday, Feb. 7.
The senior exemption and senior freeze for Cook County property taxes must be renewed every year.
The assessor's office said over 270,000 applications were mailed in early January to seniors who received the exemption last year. Approximately 80,000 seniors who received that notice have not yet renewed their exemptions.
According to the assessor's office, the senior property tax exemption is available to people who were born in 1952 or earlier; owned the property or have a contract that makes the responsible for real estate taxes; and the property was used as their primary residence.
The senior freeze exemption is available to people born in 1952 or earlier; had a total household income of $65,000 or less for tax year 2016; owned or had a legal interest in the property between Jan. 1, 2016 and Jan. 1, 2017 and used it as their primary residence; and were responsible for payments of 2016 and 2017 property taxes.
For more information or to obtain an application visit www.cookcountyassessor.com or call 312-443-7550.