During the lifetime of the conference, most of these ten very small rural schools have remained in the league in one form or another.
[1] Rutland joined the Tri-County in the early 1930's, however, they would leave for the Mid State Conference during a consolidation with the Minonk-Dana School District in 1956.
Students from Lostant were given options to attend one of four nearby schools; Fieldcrest, Putnam County, Streator, or LaSalle-Peru.
[2] During the tenure of the Tri-County, schools like Eureka, Bureau Valley, and Peoria Christian joined and left.
Bradford High School, who joined the league in 1994, was deactivated in 2001 based on low enrollment.
Students from Bradford were given the choice of attending Bureau Valley, Henry-Senachwine, or Stark County High Schools.
[3] Seneca, also a partial member of the Tri-County, plays in the Vermilion Valley (South) Conference for football.