The Council of Governors was presumably an organization of planetary leaders of Federation worlds.
In 2376, a meeting of the Council of Governors was held on Pacifica. Among the governors in attendance was Nanietta Bacco of Cestus III. Also present to address the gathering were Federation President Min Zife, and Starfleet Admiral William Ross. (TNG novel: A Time for War, A Time for Peace; ST novel: Articles of the Federation)