Jerry Whittle from O'Fallon Illinois on 7/29/2024 9:40:04 AM:
There's the Busch Greenway, Duckett Creek Trailhead which is near the Research Park and the water treatment plant.
Another would be the Weldon Spring Site Interpretive Center where nuclear waste is covered by a huge pile of rocks. However going down Hamburg Hill is not for the faint of heart even with a gravel or mountain bike.
The Defiance trailhead is a little further away, but then there's places to eat when you get done with your ride.
However as noted before, the Weldon Springs trailhead is probably the best.