Most homers in one road park in one season for one batter.

See the previous post.

A friend suggested that I send my question to David Vincent.  I did and received a prompt reply.   Thank you, David.

Only three batters did it after expansion in 1961 (AL) and 1962 (NL), which reduced the number of games between teams from the high of 22 (11 home, 11 road).

David sent this:

Here is what I found.
Most in Park by Visitor (Season)
 1 Harry Heilmann        10
  Shibe Park, 1922
 2 Lou Gehrig             9
  Sportsman's Park III, 1931
  Jimmie Foxx            9
  Tiger Stadium, 1932
  Stan Spence            9
  Sportsman's Park III, 1943
  Joe Adcock             9
  Ebbets Field, 1954
  Willie Mays            9
  Ebbets Field, 1955
 7 Babe Ruth              8
  Sportsman's Park III, 1923
  Babe Ruth              8
  Fenway Park, 1927
  Bill Terry             8
  Sportsman's Park III, 1927
  Jim Bottomley          8
  Baker Bowl, 1929
  Babe Ruth              8
  Shibe Park, 1930
  Lou Gehrig             8
  Shibe Park, 1932
  Mel Ott                8
  Baker Bowl, 1934
  Lou Gehrig             8
  League Park IV, 1936
  Joe DiMaggio           8
  Sportsman's Park III, 1936
  Joe DiMaggio           8
  Sportsman's Park III, 1937
  Jimmie Foxx            8
  Sportsman's Park III, 1939
  Babe Dahlgren          8
  Shibe Park, 1939
  Stan Musial            8
  Polo Grounds V, 1948
  Willie Mays            8
  County Stadium, 1961
  Jim Gentile            8
  Wrigley Field, 1961
  Boog Powell            8
  Robert F. Kennedy Stadium, 1964
  Mike Schmidt           8
  Wrigley Field, 1980
  Sammy Sosa             8
  Minute Maid Park, 2001

A quick glance suggests that there may be multiple four home run games.  I'll research the details.