All roads, highways and ferries that have been laid out or appointed by virtue of an act of the General Assembly, an order of court or an order of the governing body of any county are declared to be public roads and ferries, and the county supervisor and the governing body of the county shall have the control and supervision thereof. The county supervisor and governing body of the county may order the laying out and repairing of public roads where necessary, designate where bridges, ferries or fords shall be made, discontinue such roads, bridges and ferries as shall be found useless and alter roads so as to make them more useful.