Like in other sports there are designated places and spots where certain sporting event are held. In Cross Country we run at different school courses. Usually school courses host both the Varsity course and the 2.1 course. The Varsity course is different in the fact that the varsity runners must run an additional loop or extra ground to cover the 3.1 mile requirement for their race, unlike varsity the rest of the team runs the standard 2.1 mile course.
Before the start running groups, JV (Junior Varsity), FS ( Freshman and Sophomores) and Varsity are assigned to a designated box. Within this box is the line for the team to start off in. Usually the fastest starting runners in front. For big groups usually the first 5 fastest runners are in front. This is common because they are like the pace setters for the rest of the team behind them. Through out the course there are markers that signal which direction the runners should be going. The markers, and guidelines for the directions of the course are taken seriously, if a runners goes off the course they are immediately disqualified.
http://en.wikipedia.org/wiki/Cross_country_running