On May 8, McGwire hit career home run number 400 in his 4,726th at bat, faster than any other player in history who reached 400 home runs.
Facing Liván Hernández on May 16, McGwire hit his longest home run of the season, estimated at 545 feet.
McGwire hit home run number 50 of the season on August 20, becoming the first Major League ballplayer in history with three consecutive 50-plus home run seasons.
McGwire broke Roger Maris' 37-year-old record of 61 home runs on September 8 with a low line drive over Busch Stadium's left field fence. Known for hitting many long home runs, it was ironically the shortest home run McGwire hit that season.
Entering the game on September 27 against the Montreal Expos, McGwire had 68 home runs. In the third inning, McGwire hit a home run off of Mike Thurman, and in the seventh, he got number 70 off of Carl Pavano. The ball was caught by Philip Ozersky.[7] In January 1999, Todd McFarlane purchased Mark McGwire's 70th home run ball from the 1998 season for a record $3 million.[8]
A section of Interstate 70 running through downtown St. Louis was renamed "The Mark McGwire Highway." His record stood until Barry Bonds hit 73 in 2001. In years following, revelations of the anabolic steroids scandals have possibly tainted these records, but at the time it was great theater and was largely responsible for drawing many fans back to the game after the 1994 players' strike, which had angered and alienated many of them.
Note: Pos = Position; G = Games played; AB = At bats; R = Runs; H = Hits; HR = Home runs; RBI = Runs batted in; Avg. = Batting average; SB = Stolen bases
^Great Baseball Feats, Facts and Figures, 2008 Edition, p.260, David Nemec and Scott latow, A Signet Book, Penguin Group, New York, ISBN978-0-451-22363-0