Infield

In baseball and softball, the infield is the part of the field inside the four bases—home plate, first base, second base, and third base. It includes the diamond-shaped area formed by those bases, the pitcher's mound, and the surrounding dirt, with grass typically marking the outer edge of the infield. The infield is distinguished from the outfield by surface and play emphasis, and field dimensions can vary by league and ballpark.

The infield is primarily defended by the infielders—usually the first baseman, second baseman, shortstop, and third baseman—along with the pitcher and catcher who operate within or near the infield during plays. Infielders field ground balls, cover bases on force plays, and work to turn double plays. The infield surface is often dirt or a dirt-like material to aid footing and throwing, though some parks use turf or mixed surfaces, which can influence ball behavior and maintenance.

In softball, the concept is similar, with a smaller field and typically a different layout, but the infield still denotes the area inside the four bases and around the pitch area. The term can also appear in discussions of stadium design and field maintenance, where the infield encompasses the interior portion inside the outer boundary of the field.

Overall, the infield forms the core zone for many defensive strategies and in-game plays, contrasting with the outfield, where balls hit beyond the infield are typically fielded.