The Antelope Island Marathon has four distances. Full Marathon, Half Marathon, 10K and 5K. All the distances are on Antelope Island. Antelope Island is home to 600 bison and the largest island on the Great Salt Lake. This course is a true marathon in that it is not all downhill like many. There are several rollers for the runners. The views of the race have the Great Salt Lake to the East and Antelope Island mountain on the West.