Randy on 3/16/2012 3:04:45 PM:
There is a public parking garage located two blocks north of the visitor center, at the corner of N Mechanic and Frederick Streets. The fee is approx. $4 per day. It should be fairly secure. There is also C&O Parking under I-68, but this is isolated. It may be fairly secure. I have not heard of any issues. Don't leave any valuables out in the open, including coins.