1964 Annual Gathering of North American Mensa
The 1964 Annual Gathering of American Mensa (actually North American Mensa at the time, since it included Canada), International AG, was held in New York, New York (the second of four consecutive New York AGs) at the Biltmore Hotel (the first of three consecutive AGs at this venue). It lasted from June 19th through June 21st. There were 280 attendees. Brian Heald was the AG chairman.
The "International AG" title indicated that this was intended as an international gathering of Mensa rather than just an American gathering; at the time, American Mensa was in its early stages of getting organized, and the bulk of Mensans were still in the United Kingdom. The 2006 World Gathering is a related concept, but on a much bigger scale.
1963: New York
| Annual Gathering of American Mensa
1965: New York