A cattle guard has a grid with a plurality of spaced bars lying transverse to the direction of travel across the guard. The bars are supported by a plurality of spaced beams lying beneath the bars. The grid, in turn, is supported by a base in the ground. The base comprises a pair of side members positioned transverse to the direction of travel across the guard. Each of the side members has a side wall with a box-like flange member lying normal to the side wall and extending into the base. The grid rests on the flange member when the cattle guard is assembled and retained in position with respect to the base by locking elements. A plurality of columns extend between upper and lower walls of the flange member to support the grid. The base has a pair of end walls fastened to the side members during installation to complete the construction of the base.
