The very first post on The Fluxus Blog said that Fluxus arrived in America in 1962. While 1962 may have been the year of the first Fluxus exhibition in America, Fluxus was happening in New York in the 1950s.
In the years 1957 to 1959 John Cage was teaching a music composition course which was attended by many of the early Fluxus activists, including Dick Higgins, George Brecht and Al Hansen. This was also where and when Allan Kaprow first conceived of, and exhibited his happenings, and other Fluxus artists were creating art and music events and were producuing the scores to performing the events.