Odessa was originally called Millcreek. Its name was changed in 1854 to commemorate the battle during the Crimean War. Here is a link from the community with its history:
https://naturallyla.ca/living-in-lennox-addington/township/odessa/
It is officially Odessa, Loyalist Township, Lennox and Addington, Ontario, Canada. WikiTree has a place name listed for Loyalist Township, Lennox and Addington, Ontario, Canada.