The table below displays the nominal (i.e., marked) and the approximate actual outfield dimensions of all major league baseball stadiums since the early 20th century. Of particular interest are the estimates of the dimensions in the "power alleys," defined as the angular midsection between the bases. Most discrepancies arise because the power alley distances are marked either to the right or left of the "true" power alleys, but there are some cases of outright mistakes, as well. In many stadiums, the center field distance is marked at a point away from true center field. (Some of these data are also shown on the Stadium statistics page.) If the discrepancy is less than five feet, I use the nominal dimensions and the data are displayed across two columns. My approximations are based on the revised version stadium diagrams in the standard layout (with center field at top), some of which are works in progress, not yet "ready for prime time." Stadiums are listed in chronological order, according to when they were first used in the major leagues, not necessarily when they were built. There is one line entry for each stadium, even for those that went through two or more distinct "phases." Some of the respective stadium pages contain additional data. Finally, the standard caveat applies: data are subject to revision, especially on new baseball information reference pages such as this one.
