The Western Tri-State League was a professional baseball league, which was formed in 1912, and disbanded in 1914. It was a Class-D league. Over its three year existence, the league featured six teams from six different cities in Oregon, Idaho, and Washington. Two teams, the Pendleton Buckaroos, and the Walla Walla Bears, spent all three seasons in the league. The Pendleton Buckaroos won two league championships, the first coming in 1912, and the other in 1914. The Walla Walla Bears won the first-half league championship in 1913, while the Boise Irrigators were the second half champions. In 1913, the league opened with six teams, two more than the previous year. However, early into the league, two teams were dropped due to financial strains. In 1915, the league folded. Initially, it was attributed to financial difficulties. However, it was later said to be issues with the relations of team owners.
1912 Boise ID, LaGrande OR, Pendleton OR, Walla Walla WA
1913 Baker City, OR and Yakima, WA entered the league.
1914 Boise and LaGrande left the league.