A standard orienteering course consists of a start, a series of control sites that are marked by circles, connected by lines and numbered in the order they are to be visited, and a finish. The control site circles are centred around the feature that is to be found; this feature is also defined by control descriptions (sometimes called clues). On the ground, a control flag marks the location that the orienteer must visit.
The route between “controls” (refers to the flag or the site) is not specified, and is entirely up to the orienteer; this element of route choice and the ability to navigate through the forest are the essence of orienteering.
Most orienteering events use staggered starts to ensure that each orienteer has a chance to do his or her own navigating, but there are several other popular formats, including relays and events in which the orienteer must find as many controls as poss ible within a specified time.