Single-track mountain bike trail system within an hour of Madison and Milwaukee and two hours of Chicago make these trails the most popular in the state. The rugged terrain, hills and kettle-like depressions make for some tough riding, and may not be for everyone. But for riders looking for challenging, technical riding - this is the place. These trails are not suited for road or touring bikes, or bikes with trailers. During the winter, these trails are open to hikers and snowshoers. Fat-tire bikes use this trail in the winter as well.