Data for the above chart comes from Wikipedia
The Church of Jesus Christ of Latter-Day Saints is a truly world wide organization with congregations and temples scattered throughout the world. However the Church began in the United States and that is where it is headquartered.
Although right now there are more temples outside the US than inside, those inside the US are much larger. This makes sense because the world is a very big place and members are more spread out outside the US than they are within it. It also makes sense to put the largest temples where the heaviest concentrations of Church members are. Since Utah has the most members, more than half of the 20 largest temples in the world are located within that state. Above is a chart showing the square footage of the 20 largest temples in the world in blue and the 20 largest temples outside the US in orange. The Mexico City and Cardston Alberta temples appear on both sides of the chart because they are the only temples outside the US among the 20 largest in the world.
Payson Utah Temple
11 of the 20 largest temples are in Utah. With 188 dedicated temples there are 19 temples in Utah with a total square footage of 1,818,010 (168,899 m2) or 25% of the total square footage of all temples.
Gilbert Arizona Temple
2 of the 20 largest are in Arizona, and 2 are in California. No other state or province has more than one. All but 2 of the top 20 are in the US.
São Paulo Brazil Temple
Of the largest temples outside the US: South America has six, Europe has five, North America has four, Asia has four and Australasia has one.
Los Angeles California Temple
The largest temple outside Utah is Los Angeles California at 190,614 sq. ft. (17.709 m2) (Los Angeles California Temple). The Los Angeles California temple was larger than Salt Lake when the Church dedicated it but the Church made additions to Salt Lake (a multi-story annex, a new entrance, underground dressing rooms, etc.) between 1962 and 1967, making it the largest and the only temple with more than 200,000 sq. ft. (18.500 m2) (Los Angeles Times: From the Archives: The Los Angeles California Temple and The Design, Construction, and Role of the Salt Lake Temple)
Mexico City Mexico Temple
Preston England Temple
With 188 dedicated temples the total square footage of all operating temples is 7,169,808
(666097 m2) with those inside the US totaling 4,607,553 (428056 m2) (64%) and those outside the US totaling 2,562,255 (238,041 m2) (36%).
With 188 dedicated temples the total number of operating temples inside the US is 90 (48%); the total number of operating temples outside the US is 98 (52%) (Temples List).