Why was the Gettysburg Address given? What was going on the day it was given? Where was it given?

The Gettysburg Address was given in Gettysburg, Pennsylvania, following the Battle of Gettysburg in order to commemorate those who lost their lives in the battle. The conflict was a prolonged, 3-day battle (July 1–3, 1863). It resulted in more casualties than any other Civil War battle, and it is considered the turning point of the War.
Lincoln came to the site on November 19, 1863 to give this speech, commemorating the troops and reassuring the Union of their resolve to fight and win this war. The overarching theme in the speech was exemplified when Lincoln said that they would resolve to continue fighting for this nation and that a new form of government—of, by, and for the people—would emerge stronger than ever.