Justin Upton
Ted William's longest home run in Fenway Park was 502 feet, but I don't know if that was his longest home run ever.
The longest home run was made by Ryan Howard. 536 ft.
Ronnie Green of the KC Royals hit the longest home run at Fenway Park in 1987
The longest home run of 2009 belongs to Waldemar Balentien of the Cincinnati Reds. It was measured at 495 ft.
507 feet by prince fielder
603 ft
760 ft.
405'
Canseco
525 feet
Mickey Mantle
Celtic.