The Suzuki Midnight Sun Run starts on the road Engjavegur close to Laugardalshöll Sports Hall and the ice skating rink in Laugardalur. The race ends on a path by the old laundry springs in Laugardalur called "þvottalaugavegur". Half marathon and 10 k race start at 21:00 and the 5 k race starts at 21:20. The race is mostly on paths. On the following picture, you can view the start and finish area.
You can see the course map here.