Helena, Ark., on the Mississippi River, was an important staging point for units training and preparing for further action on down the Mississippi. It was overcrowded with troops and health conditions were poor. However, the 36th soon commenced a physically rigorous daily regimen of drill and building of fortifications in anticipation of an expected Confederate attack in late June of 1863. The 36th Regiment had the assignment to build breast works and trenches in support of Battery A at Fort Curtis, located on the north side of the Union defenses. Together with the 33rd Iowa infantry, they dropped trees across the roads surrounding the town of Helena to help protect against attack. The Union or federal line ran in a semicircle around the town as it faced the Mississippi River.
At the same time, Union General Ulysses S. Grant continued to attempt to encircle the town of Vicksburg, Miss. with his federal army, which included many Appanoose County men from the 6th Iowa Infantry, Company D stationed near Haynes Bluff. Grant then laid siege to the town of Vicksburg in an effort to force surrender and open up the Mississippi River to Union control.
Finally, on July 4, 1863, a Confederate force, at first estimated at between 8,000 –10,000, attacked Helena from three sides. It was a Confederate attempt to relieve pressure on the besieged city of Vicksburg. It was to occur on the very same day as the Union attack and victory in the Battle of Vicksburg. Major General Benjamin M. Prentiss originally had at Helena about 20,000 federal troops, but most had transferred in June to Vicksburg to strengthen the siege, leaving only about 4,600 troops behind to defend Helena.
At Helena, the Union forces fought a savage, bloody, all-day attack under a burning hot sun. They had the fire support of the U.S. Navy gunboat Tyler anchored in the river offshore. The Confederates under Lt. General Theophilus H. Holmes had planned a coordinated attack from three sides of the city. They nearly succeeded in capturing some of the federal redoubts with deadly hand-to-hand combat. But Helena’s defenses proved to be too strong.