| 1. | Letterboxing Central | | | Introductory information, message board, resources, links to clues, and tips for letterboxing with dogs. www.letterboxingcentral.com |
| 3. | Mirkwood's Letterboxing Site | | | Clues to letterboxes placed by the author throughout Michigan, plus images of the stamps she created for them. www.ruthannzaroff.com |
| 4. | Letterboxing North America | | | Instructions for getting started, FAQs, mailing list, and clues for letterboxes in Canada, United States, Bermuda, Mexico, and Central American and Caribbean countries. www.letterboxing.org |
| 6. | Dartmoor Letterboxes | | | Personal page with an introduction to letterboxing, terminology, stamp samples, and tips for getting started in the Dartmoor region. www.letterboxer.co.uk |
| 8. | Silent Doug's Letterboxing Site | | | Articles including getting started, outdoor ethics, and explanation of cryptic letterboxer codes. Also includes list of boxes found and clues for boxes placed in New York and Pennsylvania. www.letterboxing.info |
| 9. | Dartmoor LetterBoxes | | | Introduction, tips and things to avoid, news, survey, and box clues for the Dartmoor area. www.plympton.info |
| 10. | What is Letterboxing? | | | Personal page of Michelle Spalding with brief history and a description of the activity. www.gigagraphica.com |
| 12. | Letterboxing Northeast | | | Articles on eraser art, photographs of people and places, links, and a lengthy list of clues for boxes placed by the Drew family primarily in New England states, but also Washington, DC, South Carolina, and Colorado. hometown.aol.com |
| 13. | Wanda and Pete's Letterboxes | | | Clues for boxes placed primarily in Rhode Island, but a few in other states as well. Also includes logs of the movement of hitchhiker boxes, primarily in New England. alum.wpi.edu |
| 14. | Thinking Inside the Box | | | Washington Post article by Caroline Kettlewell which describes her discovery of the activity. www.washingtonpost.com |
| 15. | Der Hand-Carved Stamps | | | Clues for boxes planted in Oregon and several other western states, and instructions on how to carve a stamp. members.aol.com |
| 16. | British Columbia Letterboxes | | | Introduction, photographs of personal stamps, and clues for boxes planted in southwest British Columbia. www.ajaster.com |
| 17. | Letterboxing | | | Clues for boxes planted in Washington and Massachusetts. sophia.smith.edu |
| 19. | Ryan's Letterboxes | | | Personal page with clues for boxes placed throughout the western United States, as well as a few in Canada, Africa, and Central America. Also includes tips for improving the stamp quality. www.geocities.com |
| 21. | Perfect Circle Letterboxing Guild | | | Group which organizes letterboxing and geocaching expeditions throughout New Jersey. Includes clues for placed boxes and photographs from gatherings. www.pcdx.com |
| 24. | Letter-Boxing.com | | | Events in Michigan, U.S.A. and a form for suscribing to a mailing list. www.letter-boxing.com |
| 25. | Kansas Letterboxes | | | Information about letterboxing and clues for letterboxes located in Kansas. www.angelfire.com |
| 26. | Letterboxing Family Fun | | | Brief article includes details on supplies and features instructions for participation with children. raisingboys.allinfoabout.com |
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