765 Ill. Comp. Stat. 605/18.6

Sec. 18.6. Display of American flag or military flag. (a) Notwithstanding any provision in the declaration, bylaws, rules, regulations, or agreements or other instruments of a condominium association or a master association or 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. "Board" includes a board of managers or a board of a master association or a common interest community association. "Military flag" means a flag of any branch of the United States armed forces or the Illinois National Guard and the Honor and Remember Flag 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. (Source: P.A. 103-409, eff. 1-1-24.)