<page_title> List of Major League Baseball progressive single-season home run leaders </page_title> <section_title> Single-season records </section_title> <table> <cell> Mark McGwire <col_header> Batter </col_header> </cell> <cell> 1998 <col_header> Year </col_header> </cell> <cell> 70 <col_header> HR </col_header> </cell> </table>
McGwire holds the major league record for home runs in a single season (70 in 1998).