Wikipedia
Bikecentennial '76 was an event consisting of a series of bicycle tours on the TransAmerica Bicycle Trail across the United States in the summer of 1976 in commemoration of the bicentennial of America's Declaration of Independence. The route crossed ten states, 22 national forests, two national parks, and 112 counties between Astoria, OR, and Yorktown, VA, a distance of about . The route was chosen to take cyclists through small towns on mostly rural, low-traffic roads.
About 4,100 riders participated in the event, representing all 50 states and many foreign countries. Several route options were available to the participants, ranging from an 82-day, 4,250-mile cross-country trip to a more modest 12-day trip through the Rocky Mountains. Roughly 1,750 cyclists were signed up to ride the entire length of the trail. Most of the participants rode in prearranged groups of 10 to 12 with a group leader, while about a quarter rode solo. The riders were essentially self-contained; they carried camping gear, food, and other necessities in panniers on their bicycles.
Bikecentennial had been a 501(c)(3) nonprofit since 1974, and after the 1976 event the organization lived on to serve the needs of traveling cyclists, developing more routes and making maps. Bikecentennial changed its name in 1993 to Adventure Cycling Association.