Navigation Information Connection
- Links and photos associated with the U.S. Inland Waterway System. Includes real time location and queue lists of towboats and barges operating on U.S. inland waterways.
- http://www2.mvr.usace.army.mil/NIC2/default.cfm

The Complete On-Board Celestial Navigator
- About a reference book for navigation at sea. Includes table of contents and purchasing information.
- http://www.netspace.net.au/~gbennett/

Digital Navigation Publications
- Downloadable publications from the National Imagery and Mapping Agency including The American Practical Navigator and Radio Navigational Aids.
- http://164.214.12.145/pubs/

Sailing Issues: Navigation Course
- Contains nine chapters covering piloting, plotting, navigation aids, and tides. Related equations and tables.
- http://www.sailingissues.com/navcourse0.html

Celestial Navigation Data
- Astronomical information necessary to plot navigational lines of position from observations of the altitudes of celestial bodies from the U.S. Naval Observatory.
- http://aa.usno.navy.mil/data/docs/celnavtable.html

Bowditch Online
- Navigation course containing 38 chapters covering charts, radar, astronomy, and regulations. Glossary. Archives for the navigation mailing list.
- http://www.irbs.com/bowditch/