Lewis & Clark Marathon - September. The marathon follows a narrow loop course that travels alongside the Missouri River, both north and south of historic St. Charles. Because it follows the river, the course is very flat, with the exception of a half-mile section of rolling hills at the southern turnaround. Marathoners will complete the same loop twice. Starting from the St. Charles Family Arena, participants travel north past the Lewis & Clark Campsite and through St. Charles' antique district to the northern turnaround, located in Point DuSable Park. Participants then turn south and hop on the smooth gravel, easy-on-the-legs Katy Trail, a converted railway that will take them to the southern end of the course, where participants will trade the trail for the roads for the trip north, back to the start/finish area. Both courses are USATF certified. The marathon course can be used as a Boston Marathon qualifier. The course will be closed at 3:00 p.m., eight hours after the start, allowing us to accommodate marathoners who can maintain a pace of 18:20 per mile or faster.