A three-mile race is almost invariably two circuits of a typical point to point course although there are one or two exceptions (e.g. Larkhill in Wiltshire). Every course must have a minimum number of 18 fences and at least two fences must have ditches. This however can be reduced if certain fences are unfit or unsafe to be jumped (e.g. due to ground conditions or a fallen horse being in the way). The fences are made of birch and are approximately 4 foot 6 inches high.