When the United States announced their schedule for the first half of 2015, it included an April 15 friendly against Mexico, but there was no information on where it would be, aside from in the U.S. somewhere. It appears as if they have found a site though: the Alamodome in San Antonio, TX.
According to the San Antonio Business Journal, both countries have agreed to the Alamodome as the site of the match. The clash will come on the eve of Fiesta 2015, which is the city's biggest festival and should help with bringing a full house to the 65,000-seat stadium.
It is unclear what the playing surface will be for the contest. The Alamodome has turf, which they could play on, or they could bring in temporary grass to lay over it. Neither surface will be ideal, but they are the only two options for the match.
The U.S. and Mexico last played in April of 2014, when El Tri came back from two goals down for a 2-2 draw. Both teams then went onto the World Cup and were eliminated in the round of 16.
The Americans nearly played in San Antonio last year, but the friendly against Colombia fell through. Mexico played in San Antonio last January and 54,000 fans turned out to see them play South Korea.
Unfortunately, this match will not fall on a FIFA international date so clubs will not be required to release players for the match. Presumably, MLS and Liga MX have agreed to let players from their leagues play and the match will feature players from those two leagues.
The U.S. and Mexico will use the match as part of their preparations for the 2015 Gold Cup in July, as well as the start of 2018 World Cup qualifying in November.