This is the event that has everything -- famous historical sites, low traffic roads, breathtaking scenery, and plenty of climbing along well marked routes.
Event details and schedule
The Civil War Century is an event with five different routes that are designed for different ability levels, from the 25 mile Covered Bridge Quarter Century for beginners and those that don't ride long and hilly rides up to the 100+ mile Civil War Century which is intended for experienced, well trained cyclists that have done at least a couple of centuries already. For the history buff, you can visit Crampton's Gap, South Mountain, Antietam and/or Gettysburg battlefield sites. You'll see all four if you elect to ride the full century.
Baltimore Bicycling Club