Most wins in a season: 87 in 1921
Most losses in a season: 73 in 1909
|1909||Pittsburg Pirates||Western Association||52||73||Roster||Stats|
|1921||Pittsburg Pirates||Southwestern League||87||63||Roster||Stats|
Average attendance is based upon the number of actual home dates where known (most leagues from 1992 and later). Where the number of home dates is not known, the average is calculated using half the team's total games.