Visit the scenic Tunnel Bike Trail. The northern trail head is located in Harrisburg with plenty of convenient parking to get you started.It is one of the best bike trails in the midwest. It stretches 45 miles from Harrisburg to Karnak with headquarters in Vienna. Southern Illinois' Tunnel Hill State Trail is a gem of a route, with 23 trestle bridges (including one that is 450 feet long), several ghost towns, a beautiful park, a comfortable trailhead in Vienna Station and, of course, its namesake tunnel—an impressive corridor that once measured 800-feet-long until a collapse in 1929 shortened it by some 300 feet.
The first railroad tracks laid on this corridor caused such a stir that in 1870, local farmers, anticipating shipment-ready crops, planted orchards even before the line's tunnel was complete. In 1991 the original corridor of 47.5 miles was donated to the state, and just 10 years later, it was opened to the public as a multi-use trail.