Illinois Statutes Chapter 55. Counties § 5/2-3001. Definitions

a. “District” means a county board district established as provided in this Division.

b. “County apportionment commission” or “commission” means the county clerk, the State's Attorney, the Attorney General or his designated representative and the chairmen of the county central committees of the first leading political party and the second leading political party as defined in Section 1-3 of The Election Code. 1

c. “Population” means the number of inhabitants as determined by the last preceding federal decennial census. For the reapportionment of 2021, “population” means the number of inhabitants as determined by the county board by any reasonable method, including, but not limited to, the most recent American Community Survey 5-year data.

d. “Member” or “board member” means a person elected to serve on the county board.