Bondurant–Farrar, Collins–Maxwell–Baxter, Colo–NESCO, Gilbert, Madrid, Ogden, and Woodward-Granger had joined, while Carlisle, Johnston, Nevada, and North Polk had departed.

In the 2010 season, Colo–NESCO jumped to Iowa Star Conference in every sport except sharing with CMB in soccer.

In 2017–18 season, Collins-Maxwell & Baxter split up their sharing agreement and both schools went to the Iowa Star Conference.

In 2018, both Gilbert and North Polk agreed to leave the HOIC for the Raccoon River Conference in the 2020–21 school year.

[5] In March 2024, the conference extended an official invitation to Boone, which would be effective for the 2025-26 school year.