The Athletics farm system consists of six Minor League Baseball affiliates across the United States and in the Dominican Republic.
The longest affiliation in team history was the 30-year relationship with the Class A-Advanced California League's Modesto A's from 1975 to 2004.
Geographically, the Athletics' closest domestic affiliate is the Single-A Stockton Ports of the California League, which are approximately 45 miles (72 km) away.
[2] Prior to the 1963 season, Major League Baseball (MLB) initiated a reorganization of Minor League Baseball that resulted in a reduction from six classes to four (Triple-A, Double-A, Class A, and Rookie) in response to the general decline of the minors throughout the 1950s and early-1960s when leagues and teams folded due to shrinking attendance caused by baseball fans' preference for staying at home to watch MLB games on television.
[2] The current structure of Minor League Baseball is the result of an overall contraction of the system beginning with the 2021 season.