Invitation-only relaxacon hosted by Jon and Joni Stopa at their Wilmot Mountain ski resort in Wilmot, Wisconsin, often over July 4 weekends. Guests still tell of the dozens of tents, acres of parties, special guests, and unforgettable hospitality of their hosts. Legend has it that Leonard Nimoy has hidden a buried treasure somewhere on the property, capable of being found only by true, worthy believers. Begun in 1963, the event continued for more than 39 years.

The two rules for attending Wilcon (aside from receipt of a personal invitation) were to work at least one cook crew each day and one cleanup crew each day. Failure to do so resulted in a lack of an invitation the next year. The guest lists were prepared by Joni Stopa, Midge Reitan, and Dana Siegel, who used Joni's roladex and their knowledge of fannish gossip to determine the guest list.

Lewis Grant, Jr. died at Wilcon in 1966.

According to Jon Stopa, Wilcon's roots were Midwestcon and Riverside Dive, the home of Bill Donaho, Art Saha, Chuck Friedenthal, and Danny Curren, on 110th Street in Manhattan.