Found this.
A typical football stadium can range from around 5 acres for a smaller, high school stadium, to over 150 acres for a large, professional NFL stadium.
For example, the AT&T Stadium, home of the Dallas Cowboys, has an area of 140 acres. While the Soldier Field, home of the Chicago Bears, has an area of around 23 acres.
It's also worth mentioning that the area required for a football stadium doesn't only include the field and seating areas, but also the parking lots, concourses, concessions, and other facilities that are necessary for the stadium to function. For example, a big stadium like the AT&T Stadium can hold up to 150,000 fans and it has a parking lot for around 20,000 cars.
In general, the area required for a football stadium can vary greatly depending on the specific design and requirements of the stadium, and the available land in the area where the stadium is to be built.
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