The Union, led by President Abraham Lincoln, fights against the Confederacy over issues of slavery and states' rights. Key battles include Gettysburg, Antietam, and Appomattox Court House.

President Lincoln issues the Emancipation Proclamation, declaring freedom for all slaves in Confederate territory.

Following the war, the Reconstruction era aims to rebuild the South and ensure the rights of formerly enslaved individuals. The 13th, 14th, and 15th Amendments to the Constitution are ratified during this period.