The Gilbert temple will be the 142nd temple in operation. There are 14 more under construction and another 14 announced.
Tegucigalpa Honduras was dedicated in March 2013.
At 85,000 square feet and rising to 195 feet, this will be the largest temple built in 17 years. (Mt Timpanogos and Bountiful are just over 104,000 sq feet) It will also be the largest building in Gilbert
This will be about the same size as Manti, the new Provo City, and Idaho Falls. The new Payson temple will be 96,000 sq feet
Of course Salt Lake (253,000) Los Angeles (191,00) Wash DC (160,000) Jordan River (153,00) and Mexico City (117,000) are the five largest.
Read about it here lds.org/church/events/public-invited-to-gilbert-arizona-temple
See pictures here http://www.ldschurchtemples.com/gilbert/
and here http://mormontemples.org/gilbert