There is at least one major bike trail in Indiana, the Hoosier Hills Route, crossing the southeastern section of the state. There are a number of other trails, which you can find on the well-done maps published by the Indiana DNR; I have two of them, the Dunes Area and Wabash-Wildcat Region Recreation and Bikeways Maps. There are undoubtedly others. In the near future, I hope to obtain descriptions of some of these routes. In the meantime, buy those maps from the DNR. I only know of one place that welcomes mountain bikers, France Park in Logansport, an area based around an old quarry (where there is a swimming beach and also where local scuba divers go to train and practice), that has seven miles of trails open to mountain bikers. The state forests should all be available for mountain biking, and probably the Fish and Wildlife Areas as well, although I would check here first and definitely avoid both forests and F&W areas during hunting seasons. The Hoosier National forest claims 157 miles of mountain biking trails: check this link. Chris Moellering reports: There is a nice 12-mile mountain biking trail at Huntington Reservoir (okay, now it's J. Edward Roush Lake) aka Little Turtle and Kil-So-Quah State Recreation Areas in Huntington county. It's open year-round provided it's passable. (When the reservoir is at flood stage, it is not passable, as large sections of it are under-water.)
Also check out the Indiana DNR Indiana Bike Info page.
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