San Diego 5K and 10K runs through Marion Bear Park right in the heart of San Diego. The race starts at Marion Bear Park parking area on the West side of Clairemont Mesa Blvd directly South of Highway 52. The 5K is a flat and fast out-n-back course consisting of a mix of single track, double track, and about 150 yds of road. The 10K is also a mix of single track, double track, and about 150 yds of road. The 10K course will have some technical sections as well as 2-3 creek bed crossings. These will most likely be dry but will have loose rocks. The course will start with a small loop, approx 1 mile, and then become an out-n-back. http://www.dirtdevilracing.com/races/sidewinder-10k/