A form for casting concrete columns which simulate a stack of stone blocks. The form includes first and second side sections, each including two side panels. The side sections are releasably connected together to form a rectangular frame which has closed and open positions. The frame and a base on which the frame rests supports a column side insert. The column side insert has a central opening in which a column is cast. The column side insert imparts a desired appearance to the exterior sides of the cast column. After a column is cast, the side sections are moved to an open position and the column side insert is separated from the column. The form may include inserts for forming passages in the column and for forming one or more notches in the column for receiving fence rails