55 ILCS 5/5-12001
For the purpose of promoting the public health, safety, morals, comfort and general welfare, conserving the values of property throughout the county, lessening or avoiding congestion in the public streets and highways, and lessening or avoiding the hazards to persons and damage to property resulting from the accumulation or runoff of storm or flood waters, the county board or board of county commissioners, as the case may be, of each county, shall have the power to regulate and restrict the location and use of buildings, structures and land for trade, industry, residence and other uses which may be specified by such board, to regulate and restrict the intensity of such uses, to establish building or setback lines on or along any street, trafficway, drive, parkway or storm or floodwater runoff channel or basin outside the limits of cities, villages and incorporated towns which have in effect municipal zoning ordinances; to divide the entire county outside the limits of such cities, villages and incorporated towns into districts of such number, shape, area and of such different classes, according to the use of land and buildings, the intensity of such use (including height of buildings and structures and surrounding open space) and other classification as may be deemed best suited to carry out the purposes of this Division; to prohibit uses, buildings or structures incompatible with the character of such districts respectively; and to prevent additions to and alteration or remodeling of existing buildings or structures in such a way as to avoid the restrictions and limitations lawfully imposed hereunder: Provided, that permits with respect to the erection, maintenance, repair, alteration, remodeling or extension of buildings or structures used or to be used for agricultural purposes shall be issued free of any charge. The corporate authorities of the county may by ordinance require the construction of fences around or protective covers over previously constructed artificial basins of water dug in the ground and used for swimming or wading, which are located on private residential property and intended for the use of the owner and guests. In all ordinances or resolutions passed under the authority of this Division, due allowance shall be made for existing conditions, the conservation of property values, the directions of building development to the best advantage of the entire county, and the uses to which property is devoted at the time of the enactment of any such ordinance or resolution.
The powers by this Division given shall not be exercised so as to deprive the owner of any existing property of its use or maintenance for the purpose to which it is then lawfully devoted, but provisions may be made for (i) the gradual elimination of the uses of unimproved lands or lot areas when the existing rights of the persons in possession are terminated or when the uses to which they are devoted are discontinued, (ii) the gradual elimination of uses to which the buildings and structures are devoted if they are adaptable to permitted uses, and (iii) the gradual elimination of the buildings and structures when they are destroyed or damaged in major part; nor shall they be exercised so as to impose regulations, eliminate uses, buildings, or structures, or require permits with respect to land used for agricultural purposes, which includes the growing of farm crops, truck garden crops, animal and poultry husbandry, apiculture, aquaculture, dairying, floriculture, horticulture, nurseries, tree farms, sod farms, pasturage, viticulture, and wholesale greenhouses when such agricultural purposes constitute the principal activity on the land, other than parcels of land consisting of less than 5 acres from which $1,000 or less of agricultural products were sold in any calendar year in counties with a population between 300,000 and 400,000 or in counties contiguous to a county with a population between 300,000 and 400,000, and other than parcels of land consisting of less than 5 acres in counties with a population in excess of 400,000, or with respect to the erection, maintenance, repair, alteration, remodeling or extension of buildings or structures used or to be used for agricultural purposes upon such land except that such buildings or structures for agricultural purposes may be required to conform to building or set back lines and counties may establish a minimum lot size for residences on land used for agricultural purposes; nor shall any such powers be so exercised as to prohibit the temporary use of land for the installation, maintenance and operation of facilities used by contractors in the ordinary course of construction activities, except that such facilities may be required to be located not less than 1,000 feet from any building used for residential purposes, and except that the period of such temporary use shall not exceed the duration of the construction contract; nor shall any such powers include the right to specify or regulate the type or location of any poles, towers, wires, cables, conduits, vaults, laterals or any other similar distributing equipment of a public utility as defined in the Public Utilities Act, if the public utility is subject to the Messages Tax Act, the Gas Revenue Tax Act or the Public Utilities Revenue Act, or if such facilities or equipment are located on any rights of way and are used for railroad purposes, nor shall any such powers be exercised with respect to uses, buildings, or structures of a public utility as defined in the Public Utilities Act, nor shall any such powers be exercised in any respect as to the facilities, as defined in Section 5-12001.1, of a telecommunications carrier, as also defined therein, except to the extent and in the manner set forth in Section 5-12001.1. As used in this Act, "agricultural purposes" do not include the extraction of sand, gravel or limestone, and such activities may be regulated by county zoning ordinance even when such activities are related to an agricultural purpose.
Nothing in this Division shall be construed to restrict the powers granted by statute to cities, villages and incorporated towns as to territory contiguous to but outside of the limits of such cities, villages and incorporated towns. Any zoning ordinance enacted by a city, village or incorporated town shall supersede, with respect to territory within the corporate limits of the municipality, any county zoning plan otherwise applicable. The powers granted to counties by this Division shall be treated as in addition to powers conferred by statute to control or approve maps, plats or subdivisions. In this Division, "agricultural purposes" include, without limitation, the growing, developing, processing, conditioning, or selling of hybrid seed corn, seed beans, seed oats, or other farm seeds.
Nothing in this Division shall be construed to prohibit the corporate authorities of a county from adopting an ordinance that exempts pleasure driveways or park districts, as defined in the Park District Code, with a population of greater than 100,000, from the exercise of the county's powers under this Division.
The powers granted by this Division may be used to require the creation and preservation of affordable housing, including the power to provide increased density or other zoning incentives to developers who are creating, establishing, or preserving affordable housing.
55 ILCS 5/5-12001