There were many results when I Googled
Ohio quilt retreat.
One of the results was a list of Ohio quilt guilds -
http://www.quiltguilds.com/ohio.htm Many guilds have websites that list their retreats along with details. Usually, you are expected to be a member of the guild, but not always.
Many shops also have retreat information on their windows or counters. Also, guild and retreat information can be found at quilt shows.