Mayor Brandon Johnson’s office sent a letter supporting the effort to the U.S. Soccer Federation on Oct. 7, a spokesperson said. The Chicago Sports Commission would lead the bid process. The mayor’s office has not identified a specific stadium, and the commission did not immediately respond to a request for comment.

Soldier Field is one possible venue. The stadium hosted matches during the 1994 men’s World Cup and can seat roughly 61,500 to 65,000, depending on its configuration. It drew more than 63,000 fans for a Chicago Fire match featuring Lionel Messi last month.

Another possibility could be McDonald’s Park, the soccer-specific stadium the Fire is building at The 78. The venue is projected to seat 22,000 when it opens in 2028.

Chicago has stepped away from World Cup bids before, citing uncertainty about what hosting would cost the public. In 2010, the city withdrew from the U.S. bid for the 2018 or 2022 men’s tournaments after then-Mayor Richard M. Daley’s administration balked at a commitment estimated at $10 million. In 2018, under then-Mayor Rahm Emanuel, Chicago dropped out of the bid for the 2026 men’s tournament, despite Soldier Field being on a preliminary list of potential venues.

The 2031 effort is still at an early stage, with no venue specified. Any hosting proposal could put the spotlight on how costs and responsibilities would be divided among the city, stadium operators and tournament organizers. FIFA has announced that Rio de Janeiro’s Maracanã Stadium will host the opening match and final of the 2027 Women’s World Cup.