The vote was conducted on the eve of the 2018 World Cup, which is scheduled to kick off Thursday in host nation Russian Federation.
The "United 2026" bid was selected by Federation Internationale de Football Association member nations, winning 134 votes compared to 65 for Morocco. Three cities each in Canada and Mexico will also host games.
So Morocco concentrated its pitch on the country's undisputed passion for football, the notion that Africa deserves another World Cup after South Africa 2010, its far more compact offering and Euro-friendly time zone.
Typically, the host nation gets an automatic berth in the World Cup.
Canada staged the Women's World Cup in 2015.
"We see very limited economic impact at the national level given the limited duration of the World Cup and the very large size of the country's economy", Moody's analysts said in a report last May, adding that the expected boost to tourism "will likely be short-lived".
The 2026 World Cup will expand to 48 teams from 32, and will feature a new format of 16 round-robin groups of three teams with the top two from each pool advancing to a 32-nation knockout round.
Chief among those is US President Donald Trump, whose "America First" approach might score well with his electoral base but may have made the United bid's task harder than it could ever have imagined.
"Thank you so, so much for this incredible honour". The U.S. will host 60 of the 80 matches, including the final, scheduled for MetLife Stadium outside New York City.
In the last edition of the FIFA World Cup, Nigeria were knocked out by France in Brazil.
Edmontonian Alphonso Davies, 17, was the first to speak in the United Bid's final presentation to the FIFA Congress prior to the vote.
This is the first World Cup since 2006 to be hosted in Europe.
He was suspended in December 2015 for eight years, later reduced to six, after an investigation carried out by FIFA's ethics committee.