The land, located in an area called West Valley - some 45 minutes west of Phoenix, will see the development of commercial as well as residential units.
Gates' investment group, Cascade Investment, is putting $80 million towards the new community, according to the Arizona Republic.
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A new investment firm called Mt. Lemmon invested the $80 million to get the project off the ground.
Albeit he slipped from the list of the world's richest men, the wealth of Bill Gates is still beyond the imagination of most of the people. Representatives of Gates have not responded to GeekWire's inquiries on the issue nor confirmed the connection between him and Mt. Lemmon.
"Belmont will create a forward-thinking community with a communication and infrastructure spine that embraces cutting-edge technology, designed around high-speed digital networks, data centers, new manufacturing technologies and distribution models, autonomous vehicles and autonomous logistics hubs", the firm said in a statement.
Mr Gates' decision to build his new city in Arizona will be a major boost for the state which has lifted many rules on self-driving vehicles to become a tech hub. Alphabet's autonomous auto company, Waymo announced plans to test a fleet of its driverless vehicles in Phoenix last week.
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Belmont, Arizona, which will house around 160,000 people in 80,000 homes, will embrace "cutting-edge technology" throughout the city, which is to be built on a desert area now occupied by just a few dozen people. While now without water or electricity, the city's growth would also be driven by the completion of I-11, an interstate highway connecting Phoenix to Las Vegas, Nevada.
"Finally Arizona's getting recognized for being a place for innovation", added Schott.
While it has not been announced when construction will begin, or what the total cost will amount to, there is real excitement over the prospect of chiseling a new city of the future out of a remote plot of land.
Paul Babeu, former sheriff of Arizona's Pinal County, tweeted: "The Jetsons come to Arizona".
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