How long has scouts been going for?

Lord Baden-Powell did his first experiment in scouting on Brownsea Island in 1907. He founded the Boy Scouts in England in 1908 and William Boyce founded the Boy Scouts of America in 1910 after a visit to England and meetings with Baden-Powell.

There were, however, other scouting organizations dating back to the late 1800's , mostly in the US.