This is a list of baseball parks containing slopes in a portion of their outfield areas, which were sometimes or often known to affect the course of the game when a fly ball was hit toward that area.
Terraces were common in baseball in the early days, and were typically used to make up the difference in grade level between the edge of the outfield and a nearby street, which might vary from a few feet to a very significant slope.
Many of these features were eventually covered when interior bleachers were built, but in some cases that was not possible, and the terrace remained for the life of the ballpark.
This feature is to be distinguished from the normal gradual "turtleback" grading that is or was sometimes done in baseball and football fields in order to facilitate drainage.