Historical Ballpark Database

Includes all Parks from 1901 to 2020

This database of ballpark information makes it easier to create your own players and use historical parks for new leagues that you assemble.

For every park that has been used since 1901, the database contains the wall distances and heights at seven outfield locations, the size of foul territory, playing surface, statistical park factors, and weather information.

The database work is now included with version 12 of Diamond Mind Baseball. 

Using the database

There are two ways you can use this ballpark information in Diamond Mind Baseball.

First, you can import parks from this database into your local database. When a park has been added to your database, it can be assigned to one or more teams and used in league play.

Second, you can reference parks in the historical database for use in creating and modifying players. For this purpose, there is no need to import the park into your local database first. Instead, when the player creation options window appears, just indicate that you wish to select a park from the Historical Database instead of the local one.

NOTE: The park information is intended only for use with the Diamond Mind Baseball game, and there is no way to export the information for external use. 

About our research

We once believed that accurate ballpark information was widely available and completely reliable. The Red Books and Green Books have included park dimensions for years. So have the Sporting News Guides. And we had expected to rely heavily on Green Cathedrals, which contains more information on wall distances, wall heights, and the size of foul territory than any other single source that we are aware of.

But after working on this project for several years, this belief has been shaken to a significant degree. In the introduction to Green Cathedrals, the author writes, "You will notice many inconsistencies related to: incorrect measurements; movement of home plate; re-measurements; continued club usage of old and incorrect information; failure to measure power alleys at exactly 45 degree angles ..."

Until a year ago, we thought the people behind Green Cathedrals had carefully sifted through these inconsistencies and published only the values that appeared to be valid. We now believe that a good number of these potentially inconsistent values made it into the book for readers to sort out on their own.

We spent hundreds of hours comparing the information in Green Cathedrals to other ballpark books and web sites. (Some web sites appear to have shamelessly plagiarized Green Cathedrals, by the way.) We looked at old photographs. And we got some help from a Diamond Mind customer who worked at the Hall of Fame.

Despite all of this effort, we found some cases where it was awfully hard to decide which information could be relied upon. In one case, Green Cathedrals reported a large number of unexplained changes in dimensions in a short period of time, and we were unable to verify whether the park was really being changed that often or whether we were looking at a series of inconsistent newspaper reports that nobody bothered to verify.

So our historical park database isn't perfect, and we're not sure it ever will be, though we think we're fairly close to the limit on how accurate the database can be given the sources that are available. Despite the imperfections, we think it's a valuable resource.

Going forward, you can help us make this database even better. If you spot something that appears to be wrong, please tell us about it. If you can point us toward some evidence that supports the correction you are proposing, we'll look into it and make any necessary changes.

Park Dimensions

We found a lot of variety in how park information is presented in different reference works and even within the same reference work. When a source says that it's 340 feet to left, it's not always clear whether it means straightaway left field or down the left field line. And it's not always clear whether "385 to left center" refers to a point midway between the left fielder and the center fielder or midway between the LF line and straightaway CF.

The Diamond Mind Baseball game is designed to use seven outfield measurements -- the two foul lines and five equally spaced points in between. In other words, if you divide up the 90 degree angle that is made by the foul lines, our dimensions refer to points at 15 degree intervals. When published dimensions were known to correspond to angles other than the ones we us, we used that information to estimate the distances that correspond to our system. In many cases, ballpark photos and diagrams helped us do this.

The result is a set of dimensions that may not correspond exactly to the numbers you see in reference works but which have been consistently computed to match the angles used in our game.

Statistical Park Factors

For modern seasons (1944 to the present), the statistical park factors are based on our analysis of play-by-play data. When developing these park factors, we have always used a blend of single-year data and three-year averages, taking into account any new parks or changes to existing parks that might have been made during that three-year period.

For many older seasons, we don't have enough play-by-play data to rate the parks that way. Instead, we begin with home/road information (runs and homeruns) from the Macmillan Baseball Encyclopedia. This establishes the overall effect of the park on scoring and tells us how much of that effect was accounted for by homeruns. From there, we use our knowledge of the dimensions of the park (and the others in the league) to come up with a set of factors for singles, doubles and triples that account for the remainder of the park's impact on scoring.

For some older seasons, we have reviewed all of the boxscores to compile enough home/road splits. This is a very time-consuming process, however, so it will take some time before we have updated the park factors for all pre-1944 seasons in this fashion.

Weather information

We have accurate weather information -- average temperature, rain frequency, average wind velocity, frequency with which the wind blows in each direction -- since the early 1990s. Where possible, we averaged the weather data for those years and assigned those averages to the older seasons for the same park. For older parks, we used our knowledge of the climate in that region to assign values for the temperature and rain frequency. Because wind speeds and directions depend significantly on the specific location and orientation of a park, we didn't think it was possible to make intelligent estimates of wind data based on regional patterns. So we used the default values from our Neutral Park.