Sammy Sosa hit the longest home run in home run derby. It was 528 feet, followed by 524 and 520 feet, also by Sosa.
507 feet by prince fielder
Miguel Cabrera 519ft
Albert Pujols hit the longest home run out of Busch stadium in 2011. The home run was 465 feet.
Ronnie Green of the KC Royals hit the longest home run at Fenway Park in 1987
The player who hit the verifiable longest home run is Mickey Mantle. i believe it was around 634 feet. Mickey Mantle hit the home run on September 10,1960.
The longest home run hit in Minute Maid Park was on June 6, 2008 by Lance Berkman - 472 ft.