765 ILCS 130/2

Fences four and one-half feet high, and in good repair, consisting of rails, timber boards, stone, hedges, barb wire, woven wire or whatever the fence viewers of the town or precinct where the same shall lie shall consider equivalent thereto suitable and sufficient to prevent cattle, horses, sheep, hogs and other stock from getting on the adjoining lands of another, shall be deemed legal and sufficient fences: Provided, that in counties under township organization, the electors, at any annual town meeting, may determine what shall constitute a legal fence in the town; and in counties not under township organization, the power to regulate the height of fences shall be vested in the county board.