70 ILCS 5/3: Boards of commissioners.

Every authority established under this Act shall be governed by a board of commissioners. For authorities other than Metropolitan Airport Authorities, the Greater Metropolitan Airport Authority, and the Crawford County Airport Authority, in the order finding the results of the election to be favorable to the establishment of the authority, the circuit court shall determine the population of the authority and the population of each municipality within the authority having 5,000 or more inhabitants according to the last census.