This is the cover of the Sets In Order magazine from August 1958, provided by Ron G. It celebrates the 7th National Convention held that year in Louisville, Kentucky, with a total attendance of 8,028, plus 9000 spectators.
Friday night had 5000 dancers on the floor, as seen in this picture. On Saturday night, there was 6000. Six dancers from Canada were in attendance as well as 1 from England. Indiana was the state with the highest attendance at 2187.