70 ILCS 1807/15

All property of every kind belonging to the Heart of Illinois Regional Port District shall be exempt from taxation, provided that a tax may be levied upon a lessee of the district by reason of the value of a leasehold estate separate and apart from the fee or upon any improvements that are constructed and owned by others than the district. All property of the Heart of Illinois Regional Port District shall be construed as constituting public grounds owned by a municipal corporation and used exclusively for public purposes within the tax exemption provisions of Sections 15-10, 15-15, 15-20, 15-30, 15-75, 15-140, 15-155, and 15-160 of the Property Tax Code.