70 ILCS 805/3a
Except as otherwise provided in this Section, and except as provided in Section 3c , 3d, and 3.5, the affairs of the district shall be managed by a board of commissioners consisting of 5 commissioners, who shall be appointed by the presiding officer of the county board of the county in which such forest preserve district is situated, with the advice and consent of such county board. The first appointment shall be made within 90 days and not sooner than 60 days after such forest preserve district has been organized as provided herein. Each member of such board so appointed shall be a legal voter in such district. The first commissioners shall be appointed to hold office for terms of one, 2, 3, 4, and 5 years, and until June 30 thereafter, respectively, as determined and fixed by lot. Thereafter, successor commissioners shall be appointed in the same manner no later than the first day of the month in which the term of a commissioner expires. Except as provided in Section 3c and 3d , a vacancy occurring otherwise than by expiration of term shall be filled for the unexpired term by appointment of a commissioner by the county board chairman with the advice and consent of the members of the county board. In the one district in existence on July 1, 1977, that is managed by an appointed board of commissioners, the incumbent 5 commissioners shall complete their respective terms as originally prescribed in this Act. However, upon the expiration of the terms of 2 of the incumbent commissioners on January 1, 1978, they or their successors shall be appointed to hold office for terms of 3 and 5 years, and until June 30 thereafter, respectively, as determined and fixed by lot. Furthermore, upon the expiration of the terms of the remaining incumbent commissioners on January 1, 1980, they or their successors shall be appointed to hold office for terms of 2, 4, and 5 years, and until June 30 thereafter, respectively, as determined and fixed by lot. Thereafter, each successor commissioner shall be appointed for a term of 5 years. Each member of the board before entering upon the duties of his office shall take the oath prescribed by the constitution. From the time of the appointment of the first board of commissioners, such forest preserve district shall be construed in all courts to be a body corporate and politic by the name and style determined as aforesaid and by such name may sue and be sued, contract and be contracted with, acquire and hold real and personal estate necessary for its corporate purposes and adopt a seal and alter the same at its pleasure.
In case the boundaries of a district are co-extensive with the boundaries of any county, city, village, incorporated town or sanitary district, the corporate authorities of such county (until the commissioners elected under Section 3c and 3d take office), city, village, incorporated town or sanitary district shall have and exercise the powers and privileges and perform the duties and functions of the commissioners provided for in this Act and in that case no commissioner shall be appointed for that district. The corporate authorities, other than members of a county board in counties under township organization having a population of less than 3,000,000 and members of a county board in a county not under township organization who were elected prior to July 1, 1965, shall act without any other pay than that already provided by law. The members of a county board of a county under township organization and members of a county board of a county not under township organization who were elected prior to July 1, 1965, who also act as commissioners of a forest preserve district in counties having a population of less than 3,000,000 may receive for their services as commissioners of a forest preserve district a per diem fee to be fixed by such board, but not to exceed $36 per day, which shall be in full for all services rendered on such day, or an annual salary to be fixed by such board, but not to exceed $3,000, plus mileage expenses at a rate not more than the amount allowed for members of the county board of such county, as fixed by the board, for each mile necessarily traveled in attending meetings of the board of such district, plus any expense incurred while, or in connection with, carrying out the business of such district outside the boundaries of such district, payable from the forest preserve district treasury. The president of the Board of Commissioners of the Forest Preserve District in counties of less than 3 million may receive in lieu of a per diem fee an annual salary to be fixed by such board. No Forest Preserve Commissioner shall file for a per diem payment for services rendered on the same day for which he filed for a per diem payment as a county supervisor. When the county board also acts as such commissioners, a member of the county board of a county under township organization and a member of the county board of a county not under township organization, who is elected prior to July 1, 1965 may, with the permission of the county board, work alone as such a commissioner and be paid in the usual manner.
Unless otherwise qualified, the term "board", when used in this Act, means the board of commissioners of any forest preserve district, or the corporate authorities of any county, city, village, incorporated town, or sanitary district, when acting as the governing body of a forest preserve district.
70 ILCS 805/3a