Baseball field

A baseball field, also called a ball field or baseball diamond, is the field upon which the game of baseball is played. The term can also be used as a metonym for a baseball park. The term sandlot is sometimes used, although this usually refers to less organized venues for activities like sandlot ball.

The starting point for much of the action on the field is home plate (officially "home base"), a five-sided slab of white rubber. One side is 17 inches (43 cm) long, the two adjacent sides are 8.5 inches (22 cm). The remaining two sides are approximately 12 inches (30 cm) and set at a right angle. The plate is set into the ground so that its surface is level with the field. The corner of home plate where the two 12-inch sides meet at a right angle is at one corner of a 90-foot (27.43 m) square. The dimensional specifications are technically inconsistent because the angle constraints require that the front be √2 times the length of the back, which is not equal to a 17:12 ratio, but a physically built home plate will have side lengths accurate to a few hundredths of an inch. The other three corners of the square, in counterclockwise order from home plate, are called first, second, and third base. These bases are marked by canvas or rubber cushions, 18 inches (46 cm) square and 3–5 inches (7.6–12.7 cm) thick. Adjacent to each of the two parallel 8.5-inch sides is a batter's box.

All the bases, including home plate, lie entirely within fair territory. Thus, any batted ball that touches those bases must necessarily be ruled a fair ball. While the first and third base bags are placed so that they lie inside the 90-foot square formed by the bases, the second base bag is placed so that its center (unlike first, third and home) coincides exactly with the "point" of the ninety-foot square. Thus, although the "points" of the bases are 90 feet apart, the physical distance between each successive pair of base markers is closer to 88 feet (26.8 m).

Near the center of the square is an artificial hill known as the pitcher's mound, atop which is a white rubber slab known as the pitcher's plate, colloquially the "rubber". The specifications for the pitcher's mound are described below.

The lines from home plate to first and third bases extend to the nearest fence, stand or other obstruction and are called the foul lines. The portion of the playing field between (and including) the foul lines is fair territory; the rest is "foul territory". The area within the square formed by the bases is officially called the infield, though colloquially this term also includes fair territory in the vicinity of the square; fair territory outside the infield is known as the outfield. Most baseball fields are enclosed with a fence that marks the outer edge of the outfield. The fence is usually set at a distance ranging from 300 to 420 feet (90 to 130 m) from home plate. Most professional and college baseball fields have a right and left foul pole which are about 440 to 500 feet (130 to 150 m) apart. These poles are at the intersection of the foul lines and the respective ends of the outfield fence and, unless otherwise specified within the ground rules, lie in fair territory. Thus, a batted ball that passes over the outfield wall in flight and touches the foul pole is a fair ball and the batter is awarded a home run.

A baseball infield is the square area within the four 90-foot baselines "(60-foot baselines in Little League Baseball for youths 12 years old and under)". The four bases are integral parts of the infield; a ball that touches any part of a base is considered a fair ball.

First base is the first of the four bases that must be touched by a runner in order to score a run for the batting team. The runner may continue running past first base in a straight line without being in jeopardy of being put out, so long as they make contact with first base and make no move or attempt to advance to second base.

The first baseman is the defensive player mainly responsible for the area near first base. In some youth leagues and adult recreational leagues, a "double first base" or "safety first base" is used. A double first base is rectangular (rather than square), measuring 30 by 15 inches. It is normally colored white and orange (two 15 by 15 inches squares). It is placed with the white half in fair territory and the orange half in foul territory. The white half is used by the first baseman to make plays while the orange half is used by the runner. This creates a separation between the first baseman and runner, reducing the chance of injury on plays at first base.