Step 1: Understanding the Concept:
Large-scale international sporting events occasionally employ multi-nation hosting formats to share organizational costs and maximize infrastructural capability across expansive geographical regions.
Step 2: Detailed Explanation:
The 2026 FIFA World Cup is uniquely structured as a joint North American tournament co-hosted by the United States, Canada, and Mexico. This event marks several historical milestones: it is the first tournament featuring an expanded pool of 48 teams (up from 32 teams) and the first time an edition is split across three distinct sovereign host nations. Matches are distributed across 16 designated host cities across the continent.
Step 3: Final Answer:
The host nations are the USA, Canada, and Mexico.