Site Selection for the 1959 Worldcon was conducted by Solacon, the 1958 Worldcon. There were three bidders which advertised in the Solacon Progress Reports (nearly the only formal bid activity done in advance of the convention at the time): Detroit in '59, Big 'D' in '59 and Chicago: 1959. The Dallas bid evidently did not file and was apparently not part of the site selection vote which, as was the custom of the time, held entirely at Solacon.
[The] Chair announced that two cities, Detroit and Chicago, had presented written intentions to bid before the deadline, and that nominations would be made in the order in which written intentions had been received.
Dean McLaughlin made the nominating speech for Detroit, which was seconded by Bjo Wells and E. E. Evans.
Earl Kemp made the nominating speech for Chicago, which was seconded by Roger Phillips Graham and Robert Bloch.
Ballots were distributed by representatives of the two cities, aided by two members of the Convention Committee, and the vote counting was witnessed by same. Results of voting:
Detroit: 125 Chicago: 45
Solacon's PR 2 (which still acknowledged WSFS, Inc which it did not formally reject until the opening of the convention) reports:
"Formal Notices of Intent to Bid for the 1959 WorldCon (as required by the WSFS Constitution for all prospective bidders) have been received from The Misfits, of Detroit, led by George Young, and from a Dallas group, led by Dale Hart. Chicago's interests are being advertised by Earl Kemp, although formal notice has not been received as of this writing. Both Detroit and Dallas have announced group-travel-to-South-Gate plans, described on the Travel page.
"Commenting on this, SOLACON Secretary Len Moffatt looks forward to " …a lively business meeting at SOLACON with three groups to date competing…. Cons with several groups vying for the next year's bid can be very exciting … smoke-filled rooms and all …. a very healthy sort of thing … in the great fan-convention tradition."