At the Battle of Gettysburg, the Thirteenth Independent NY Battery was part of the Artillery Brigade commanded by Major Thomas Osborn, assigned to the Eleventh Corps under General Howard. On the morning of July 1 the Corps was marching north from Emmitsburg when it received word of the first skirmishes on the north side of Gettysburg. General Howard rushed his troops to Gettysburg and through the town to aid in the ongoing battle. He also set up headquarters and a defensive position on Cemetery Hill. By evening, that position had became the artillery stronghold which denied the Confederacy victory and enabled the Union to rebuild itself for the next day's battle.

Mort Kunstler paid homage to Capt Hubert Dilger of Battery I, 1st Ohio Light Artillery, with his painting "Dilger at Gettysburg", which portrays Dilger rushing his Battery to the battle. However, when Dilger's Battery took position, the Thirteenth was there fighting at their side. The two batteries fought in the streets of Gettysburg that first day, and later on Cemetery Hill. By late afternoon of July 2, the Thirteenth Battery was exhausted and retired to the rear to replenish its ammunition and make repairs. On the afternoon of July 3, they rejoined the battle and were ordered to assist in the defense of the Second Corps under General Hancock.

The following reports were written by the participants shortly after the battle and give a first hand accounting of the Thirteenth Independent NY Battery at Gettysburg:

	Report of Major Thomas W. Osborn Commander, Artillery Brigade, Eleventh Corps
	Report of Capt. Hubert Dilger Commander, Battery I, First Ohio Light Artillery
	Report of Lieut. William Wheeler Commander, Thirteenth New York Battery
	Letter of Lieut. William Wheeler, 26 Jul 1863 Commander, Thirteenth New York Battery

Today, a large granite monument at Gettysburg National Military Park marks the site where the Thirteenth Battery fought on July 1, 1863. Nearby, a metal plaque commemorates the Eleventh Corps Artillery Brigade. Some links to additional information about Gettysburg may be found here.