Question

on september 17, 1862, the union and the confederacy fought at
antietam
first battle of bull run
chancellorsville

Explanation:

The Battle of Antietam (also known as the Battle of Sharpsburg) took place on September 17, 1862, during the American Civil War, where the Union and the Confederacy fought. The First Battle of Bull Run was in 1861, and the Battle of Chancellorsville was in 1863. So the correct answer is Antietam.

Answer:

Antietam