Intercon was held 13-14 Aug 1976 in the Tri-Arc Travelodge, Salt Lake City, Utah
As far as I know, this was the first fan-run science fiction convention ever held in Utah.
From the Salt Lake Tribune, Wednesday, June 30, 1976, page 11:
Program, courtesy of Jeri (Woods) Foster:
PDF file of the program book: Intercon 1976 Program Book
Photographs courtesy of Diane (Howarth) Anderson:
Photographs courtesy of Julia (Howarth) West:
Badge from the convention, courtesy of Jeri (Woods) Foster:
More information about the convention harvested from the Fanlore site:
A one-act Star Trek play written by Julia Howarth, “In Memorium,” was put on at Intercon. A fanzine containing the text of the play, with photographs of the original cast to illustrate it, was printed. The ‘zine is available here as a pdf file, which was scanned from the original masters for the play. (Julia is embarrassed that she did not check the spelling of ‘Memoriam’ before she typed up the play for publication.) The play tells the story of some of the scores of security guards killed in the line of duty on the Enterprise trying to talk Captain Kirk into being more careful with the lives of the remaining redshirts.
PDF copy of In Memorium