The Battle of Helena was fought on July 4, 1863, near Helena, Arkansas, during the American Civil War. Union troops captured the city in July 1862, and had been using it as a base of operations. Over 7,500 Confederate troops led by Lieutenant General Theophilus Holmes attempted to capture Helena in hopes of relieving some of the pressure on the Confederate army besieged in Vicksburg, Mississippi. Helena was defended by about 4,100 Union troops led by Major General Benjamin Prentiss, manning one fort and four batteries of artillery.

Differing interpretations of Holmes' order to attack at daylight resulted in Brigadier General James F. Fagan's troops attacking Battery D unsupported, and Major General Sterling Price's attack against the Union center was made after Fagan's had largely fizzled out. To the north, Confederate cavalry commanded by Brigadier Generals John S. Marmaduke and Lucius M. Walker failed to act in concert and accomplished little. The assaults failed, and Vicksburg fell the same day. Later in the year, Union troops used Helena as a staging ground for their successful campaign to capture Little Rock, Arkansas.

In December 1860, the state of South Carolina seceded from the United States, as a result of several disagreements with the federal government, slavery chief among them. Further Deep South states seceded early in the next year, forming the Confederate States of America. The Civil War began on April 12, when Confederate troops bombarded Fort Sumter. When Abraham Lincoln, the newly elected President of the United States, called for 75,000 volunteers to put down the rebellion, this proved the catalyst for the southern state of Arkansas to secede and join the Confederacy. Fighting occurred to the north in Missouri during 1861, but in early March 1862, Confederate forces were defeated in northern Arkansas at the Battle of Pea Ridge. Beginning in late April, Union (United States) forces followed up on the victory at Pea Ridge by moving into Arkansas, threatening the state capital of Little Rock, and occupying the Mississippi River town of Helena on July 12.

By early 1863, holding Helena provided the Union with significant advantages, such as serving as a supply depot for the ongoing Vicksburg campaign, providing a marshalling point for a future advance against Little Rock, and securing northeastern Arkansas. In late May, with Union troops heavily pressuring Vicksburg, Confederate authorities sent a message to General Joseph E. Johnston suggesting that forces from the Trans-Mississippi Department be used to relieve the pressure on Vicksburg. One idea was an attack on Helena. The commander of Confederate forces in the Trans-Mississippi, Lieutenant General Edmund Kirby Smith, was forwarded in June the dispatch that Johnston had received, and delegated making the decision whether to attack Helena to Lieutenant General Theophilus Holmes, the Confederate commander of the District of Arkansas.

On June 9, Holmes learned that the strength of the Union forces in Helena was about 3,000 or 4,000 men, and decided against an attack. He thought the attack would be too costly, and instead suggested placing an artillery battery along the Mississippi River to intercept Union shipping. Further vacillation by Holmes ended when Confederate cavalry reported on June 14 that the garrison at Helena had been weakened. He began moving towards Jacksonport and met Major General Sterling Price and Brigadier General John S. Marmaduke on June 18. There they formed a plan to concentrate Confederate forces against Helena, although Holmes was still nervous about the proposed attack, as he was worried that it might fail. He made an agreement with Price, who was much more popular with the general public, that he would publicly support the decision of the attack in the case of a failure.

Once formed, the plan called for Price, with his 3,095 infantry, to move from Jacksonport to Cotton Plant on June 22, along with Marmaduke's 1,750 cavalry; that 1,339 infantry commanded by Brigadier General James F. Fagan would move from Little Rock to Clarendon, and that Brigadier General Lucius M. Walker would screen Helena with his 1,462 cavalry. Holmes would accompany the attack. On June 22, Holmes revised the plan, ordering Price to concentrate at a location known as Switzer's, instead of Cotton Plant. Rains and high stream levels slowed Price's approach, and though Marmaduke's men reached Switzer's on time, the infantry was delayed at the crossing of the Cache River. Moving through swamps resulted in the loss of many accompanying animals and wagons. Holmes and Fagan reached Clarendon on June 26. Once there, Holmes provided further orders for the advance: Walker was to screen Fagan's movement to Helena with part of his command, while Price continued on to Helena from Switzer's. Price's advance continued to be slowed by the terrain and weather, to the annoyance of Holmes, who rightly believed that the delay had prevented any remaining chance of the movement being a surprise. The Confederate columns finally united on July 3, and that day began the final movement towards Helena. Overall, the Confederates had 7,646 men.

The Union troops in Helena were commanded by Major General Benjamin Prentiss and consisted of the Thirteenth Division of the Thirteenth Corps. Although Prentiss was in command of the general district around Helena, the garrison itself was operationally commanded by Brigadier General Frederick Salomon, the commander of the division. Salomon would make many of the decisions in the upcoming battle. Prentiss originally dismissed rumors of a Confederate attack, but by late June gave more credence to the reports. A defensive position known as Fort Curtis already existed to the west of Helena, but four new batteries, named with the letters A, B, C, and D, were ordered built. Each of the four batteries was located on a high point of Crowley's Ridge. Trees were felled in front of the Union lines, although it is unclear if they were simply left where they fell as an obstruction or were converted into abatis. Prentiss was originally intended to be reinforced by three vessels from the Union Navy, but only one, the timberclad USS Tyler, was available when the Confederate attack struck. Prentiss also cancelled a planned celebration of the Fourth of July as a precaution, and ordered the roads into town barricaded with felled trees. The Union garrison would face the coming attack with 4,129 men. Remembering the surprise suffered by men under his command in the earlier Battle of Shiloh, Prentiss ordered reveille blown daily at 2 am. Prentiss' men had advantages over the Confederates through their defenses, batteries, and naval support. The Confederates had support from the local white populace.

On July 3, Holmes, Price, Walker, Fagan, and Marmaduke gathered to formulate the plan of assault. Holmes noted that the defenses of Helena were stronger than he expected but carried on with the attack anyway. Price was to attack the Union center, focusing on Battery C on Graveyard Hill. South of Price, Fagan was to attack Battery D on Hindman's Hill, while Marmaduke, supported by Walker, was to attack from the north, take Rightor's Hill, and then use the hill as an artillery position to fire on Batteries A and B. Walker's specific orders were to "act against the enemy as circumstances may justify", a vague order that left him under his own initiative and resulted in him accomplishing little in the coming battle. Holmes made a pledge that he would take personal responsibility for the results of the assault if it failed. The converging attack would be difficult, and the generals interpreted Holmes' order to begin the attack at "daylight" differently. Historian Robert Kerby describes the Confederate plan as "a model of brutal irresponsibility". Since Prentiss was aware of a coming attack, the Confederates would not have the advantage of surprise. Their plans were also hampered by poor reconnaissance.