Sir Robert Baden-Powell, founder of the Scouting movement, created the idea of holding a large encampment of Scouts and leaders to celebrate Scouting in England. He called it a jamboree.
Starting in 1920, there has usually been a World Boy Scout Jamboree every four years. (The exceptions have been the period between the 1937 Jamboree and the 1947 Jamboree, and the period between the 1975 Jamboree and the 1983 Jamboree). Several years before the event, the World Scout Committee selects a national Scout Association to host the Jamboree. And an effort is made to schedule the event on different continents of the world.
Starting in 1937, the Boy Scouts of America has held 16 National Scout Jamborees. Nearly 654,000 Scouts and leaders from across the nation have shared the jamboree experience since the first jamboree was held at the base of the Washington Monument in our nation's capital.
The nation in which the host association is located becomes the host country. Scouting has been honored philatelically by the host country for the World Boy Scout Jamboree for over 65 years. Beginning in 1929 with the III Jamboree in England, there has been some type of special cancellation. And beginning in 1933 with the IV Jamboree in Hungary, the host country has issued some type of a postal adhesive or postal card.
http://www.sossi.org/jamboree/wjnow.htm
http://www.yosemitejamboree.org/index.php?option=com_content&view=section&layout=blog&id=8&Itemid=44
