Manny Ramirez’ fourth-inning solo blast into the fifth deck off Blue Jay right-hander Chris Carpenter is the longest home run ever hit in the history of the SkyDome. The Red Sox DH’s 491-foot moon shot eclipses A’s first baseman Mark McGwire’s 1996 mark by three feet.

This Day In Baseball

On June 3, 2001 — Manny Ramirez’ fourth-inning solo blast into the fifth deck off Blue Jay right-hander Chris Carpenter is the longest home run ever hit in the history of the SkyDome. The Red Sox DH’s 491-foot moon shot eclipses A’s first baseman Mark McGwire’s 1996 mark by three feet.

Source
Baseball Reference June 3