There is a new iphone app for C&O Canal users, developed by the man who created and maintains the bikewashington.org website.

http://bikewashington.org/canal/app/

Some features:

- contains the information and maps found on the BikeWashington.org Canal web site.

- keeps track of your current location without needing a data connection, so it works in areas that have spotty cell coverage.

- displays nearby amenities.

- self contained maps detailing the entire trail, with your position and items of interest are displayed on the maps.

- an Emergency page that displays you current location (both Latitude/Longitude and Milepost), and the nearest access points to your current position. This page also provides single button dialing for the Park Emergency number or 911


I think it costs $1.99, but I don't have an iphone so I could be wrong. Anyway, it seems like a great app for anyone who spends time on the towpath.