Mill Mountain is a 1700 foot mountain sitting right in the middle of the city of Roanoke. It rises 800 feet above the city below and is adorned by the Mill Mountain Star, at 88 feet the largest freestanding illuminated man made star in the world.
Luckily for cyclists the star is not all Mill Mountain has to offer...
In 1999 the city of Roanoke built the Star Trail on Mill Mountain but it's closed to bikes. Since then volunteers have spent hundreds of hours rehabbing old trails and building new ones to provide multiuse access to the trails on Mill Mountain (the Star Trail remains closed).
The main appeal of Mill Mountain's trail system is that it is so close to such a large part of the population of Roanoke. From many areas of the city (and Roanoke County) Mill Mountain is easily accessible by bike. The trails are generally intermediate in difficulty though there is quite a bit of elevation change.
Great info about the trails including a trail map is available HERE