765 ILCS 160/1-70

(a) Notwithstanding any provision in the declaration, bylaws, community instruments, rules, regulations, or agreements or other instruments of a common interest community association or a board's construction of any of those instruments, a board may not prohibit the display of the American flag or a military flag, or both, on or within the limited common areas and facilities of a unit owner or on the immediately adjacent exterior of the building in which the unit of a unit owner is located. A board may adopt reasonable rules and regulations, consistent with Sections 4 through 10 of Chapter 1 of Title 4 of the United States Code, regarding the placement and manner of display of the American flag and a board may adopt reasonable rules and regulations regarding the placement and manner of display of a military flag. A board may not prohibit the installation of a flagpole for the display of the American flag or a military flag, or both, on or within the limited common areas and facilities of a unit owner or on the immediately adjacent exterior of the building in which the unit of a unit owner is located, but a board may adopt reasonable rules and regulations regarding the location and size of flagpoles. (b) As used in this Section: "American flag" means the flag of the United States (as defined in Section 1 of Chapter 1 of Title 4 of the United States Code and the Executive Orders entered in connection with that Section) made of fabric, cloth, or paper displayed from a staff or flagpole or in a window, but "American flag" does not include a depiction or emblem of the American flag made of lights, paint, roofing, siding, paving materials, flora, or balloons, or any other similar building, landscaping, or decorative component. "Military flag" means a flag of any branch of the United States armed forces or the Illinois National Guard made of fabric, cloth, or paper displayed from a staff or flagpole or in a window, but "military flag" does not include a depiction or emblem of a military flag made of lights, paint, roofing, siding, paving materials, flora, or balloons, or any other similar building, landscaping, or decorative component.