The Pioneer League is a professional baseball league in the United States, primarily composed of teams from the western states. It was established in 1939 and is classified as a Rookie-level league, serving as a developmental stage for players in the Minor League Baseball system. The league features teams that are affiliated with Major League Baseball (MLB) organizations. In recent years, the Pioneer League has transitioned to an independent league, meaning its teams are no longer directly affiliated with MLB clubs. This change allows for greater flexibility in team operations and player recruitment. The league continues to provide opportunities for aspiring players to showcase their talents and advance in their baseball careers.