Antietam influenced the subsequent Battle of Gettysburg by setting the stage for future confrontations.

The results of the Battle of Antietam, which included the stopping of Lee's invasion and the announcement of the Emancipation Proclamation, altered the course of the Civil War. Lee's previously unshakeable confidence was diminished by the Union's determination, while the North experienced a significant strategic advantage. In 1863, as Lee sought to launch another invasion, he intended to leverage this momentum, culminating in the crucial battle at Gettysburg. The insights gained and the changing strategies from Antietam had a direct influence on the tactics and preparations for this subsequent encounter.