What men sided with Union during the civil war?

During the American Civil War, many men from various backgrounds sided with the Union, including soldiers from the Northern states, abolitionists, and former slaves. Key Demographics included farmers, factory workers, and immigrants who sought economic opportunities and supported the preservation of the Union. Notable figures such as Frederick Douglass and military leaders like Ulysses S. Grant also played significant roles in the Union's efforts. Additionally, some Southern men, known as "Unionists," opposed secession and fought to maintain the Union.