Des Plaines River Trail Races Marathon

Four races share one October Saturday off a single Lake County trailhead, running from a half marathon up to 50 miles, and the marathon is the one that pulls goal-time runners rather than ultra people. The draw is the tread. This stretch of the Des Plaines River corridor is packed limestone, wide, and about as level as a marathon gets in the Midwest, which is why a course with the word trail in its name keeps turning out Boston times. Entry opens at the start of January through UltraSignup and stays open until the Monday of race week unless a distance fills first. Rolling an entry to the following year costs 20 percent, runner-to-runner transfers are allowed into late September, and there are no refunds for any reason, cancellation included.

All four distances work out and back along the northern Des Plaines River Trail from Half Day Forest Preserve. Marathoners go south first, turn, come back through the start area, then head north to a turnaround behind Adler Park School in Libertyville before retracing the whole thing. The surface is fine crushed limestone the entire way, wide enough to pass on and free of the roots and rock that make most trail marathons a technical exercise, and the scenery alternates between closed forest and open wetland. Bridges and viaducts carry the route under the busy roads, leaving two minor crossings on the marathon. Waves leave every three minutes to keep the early miles from bunching, six manned aid stations and two unmanned ones cover the distance, and the finish stays open until 6:30 p.m., which gives marathon starters ten and a half hours. The one real variable is water. The river floods, and when the trail goes under, the race shifts to an alternate loop that carries the same certification.

The second weekend of October in the northern Chicago suburbs is close to the best running weather the Midwest offers, with mornings in the mid 40s and afternoons near 65. Because the corridor swaps between dense forest and open marsh, shade comes and goes instead of holding steady, and the marsh sections are where a north wind gets a clean run at you. Heavy rain in the days beforehand tends to matter more than race-day temperature, since standing water and softened limestone are what actually slow this course down.