The course runs around the Samphire Hoe nature reserve and then along the sea wall in 3.71 mile loop and out and backs. The trail is very high quality, there is one little hill near the sea wall and another not too far from the start of each loop. The sea wall is concrete and flat.
8 loops of 3.71 miles will be an Ultra by 100 Marathon Club standards.
The 100 mile distance is 27 x 3.71 miles loops = 100.16 miles.
You can view the route on MapMyRun here
The total elevation gain is about 100' per loop, about 2500' for the 100 miles.
7 Laps is 25.97 miles which is cruelly close to a marathon but not quite and we do appreciate that some folk coming along for the timed challenges won't necessarily want to do a 29.68 mile ultra. So if you "just" want to do a marathon after 7 laps pick up a flag and go out on a short lap, this short lap is out as normal but turning right after the "zig zag" section. You'll be credited with a 26.5 mile marathon finish in the results. This will not be signed on the course to avoid the risk of confusion and this short lap option obviously only available after 7 laps and once taken you'll have to ring out afterwards.