I cannot locate this information anywhere! I'm, of course, referring to the football (soccer) tournament played in Spain.
The RFEF (Real Federación Española de Fútbol) officially announced that the Copa del Rey final for 2014 will be played in the Mestalla Stadium, Valencia (home of Valencia FC).
The stadium will be determined on March 4
The reference given there is http://www.marca.com/2014/02/13/futbol/copa_rey/1392248737.html
I do not speak Spanish but using Google Translate I understood that the match will probably be played in Valencia, although the decision will not be official until the next meeting of the Board of the RFEF, scheduled for March 4.