The Blackwood Marathon Relay is a five-leg event consisting of a 7 km canoe leg on the Blackwood River, starting at Jayes Bridge, followed by a 16 km horse trek across private farmland, a 1 km river swim, a 37 km cycling leg on mixed bush tracks and country roads, and a 10.5 km run finishing at the Bridgetown Sports Ground. The event can be completed by teams or as a solo challenge. The course features river scenery, rolling hills, and open farmland, with technical sections and scenic views.