There is an article at Cinncinati.com about the Siege of Cincinnati when the city was threatened by Confederate forces in the fall of 1862. More information about the volunteer militia, dubbed The Squirrel Hunter’s, who defended the city is available in the OHS Archives/Library.
There were also African American men who participated in the defense of Cincinnati. When African Americans initially volunteered as militia members, they were denied. When the threat to the city increased in September 1862, they were impressed into service to build fortifications. Their unit was designated the Black Brigade of Cincinnati. They were the first African American men in the north to participate in the war effort. Materials in the OHS Archives/Library about the Black Brigade include:
Read more about the Black Brigade of Cincinnati at the Fight for the Colors web site.