The Harry Gamble-Thompson 20Ten is a 20 mile race with a 10 mile option.
This is an ideal prep race for a spring marathon - although multiple laps are not everyone's cup of tea, there are advantages - each lap (mile) is exactly the same so you can practice your "even pace" or "negative splits" (we will record and publish your mile splits). You pass toilets and water station once a mile, and if you have someone supporting they can shout you on once or twice each lap.