The championships - which are designed for pupils who already have practical experience of the sport - have grown in recent years, with entries from all over Scotland. Perth and Kinross is expected to send 50 athletes to the event after the success of their local programme which had 1,100 pupils entered in six area championships.
In Biggar, races will be held from P5-S6 with varying degree of difficulty on a course of mixed woodland and open fields.
Organiser Blair Young, head of PE at Biggar, says he wants to make the event attractive to everyone.
Pupils can enter solo or in pairs and prizes will be awarded to the first three finishers in each race.