The First Pro Baseball Game

The first professional baseball game played under pay-for-play conditions took place in Fort Wayne, Indiana on May 4, 1871, when the Fort Wayne Kekiongas defeated the Cleveland Forest Citys 2 to 0. This single game marks the official beginning of professional baseball in the United States, predating the founding of the National League by five years. The box score from that game survives and is considered one of the most historically significant documents in American sports.

Source: Wikipedia