One of 67 Canadian cities to field MiLB Clubs since 1901, Lethbridge (Alberta) was a charter member of the fledgling Class D Western Canada League in 1907, playing as the city-sponsored Miners for three seasons before folding after the 1910 season.
The Lethbridge Expos (and later Dodgers) arrived 65 years after professional baseball left the area as part of the 4-team Rookie-level Pioneer League. After the 1983 season, the Los Angeles Dodgers ceased its affiliation, and Lethbridge's owners decided to move the now-independently affiliated franchise to Pocatello (ID) for the 1984 season.
After an 8-year hiatus, the Pocatello's team returned to Lethbridge as the Mounties for four seasons before rebranding as the Black Diamonds for the 1996 season, its first as an affiliate with the MLB expansion Arizona Diamondbacks. The Black Diamonds served as Arizona's first-ever MiLB affiliate.
Fans in Lethbridge only watched winning baseball, as the Black Diamonds earned winning records in each of its three seasons from 1996 through 1998. After the 1998 season, the Black Diamonds packed up and relocated to Missoula (MT) and continue today as the Missoula Osprey. The Black Diamonds' winning ways continued, as the Osprey won the Pioneer League title in its first year stateside in 1999.