How far apart are the bases on a baseball diamond?

On a Major League baseball diamond, the bases are 90 feet apart. Major League Baseball's official rules identify the infield as a 90-foot square. College and high school baseball infields have the same dimensions as a Major League infield.

The straight line between each base is called the baseline, although it is not painted or chalked on the field. The base path measures 3 feet on each side of the baseline. Further, the distance from home plate to the center of the pitcher's mound is 60 feet, 6 inches; the mound measures 18 feet in diameter. These measurements are also used on high school and college baseball fields.