Helena was defended by about 4,100 Union troops led by Major General Benjamin Prentiss, manning one fort and four batteries of artillery.

To the north, Confederate cavalry commanded by Brigadier Generals John S. Marmaduke and Lucius M. Walker failed to act in concert and accomplished little.

Later in the year, Union troops used Helena as a staging ground for their successful campaign to capture Little Rock, Arkansas.

[2] Fighting occurred to the north in Missouri during 1861,[3] but in early March 1862, Confederate forces were defeated in northern Arkansas at the Battle of Pea Ridge.

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.

[8] He thought the attack would be too costly, and instead suggested placing an artillery battery along the Mississippi River to intercept Union shipping.

[8] 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.

[10] 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.

[12] On June 22, Holmes revised the plan, ordering Price to concentrate at a location known as Switzer's, instead of Cotton Plant.

[13] Rains and high stream levels slowed Price's approach,[14] and though Marmaduke's men reached Switzer's on time, the infantry was delayed at the crossing of the Cache River.

[17] 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.

[23] 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.

[26] Prentiss was originally intended to be reinforced by three vessels from the Union Navy, but only one, the timberclad USS Tyler,[a] was available when the Confederate attack struck.

[24][28] Prentiss also cancelled a planned celebration of the Fourth of July as a precaution,[19] and ordered the roads into town barricaded with felled trees.

[29] Remembering the surprise suffered by men under his command in the earlier Battle of Shiloh, Prentiss ordered reveille blown daily at 2 am.

[14] Late on July 3, Fagan sent a patrol commanded by Colonel William H. Brooks to secure the junction of the two roads leading to Little Rock.

[34] To protect Fagan's flank, Brooks' men were sent up the Lower Little Rock Road at around 1:30 am;[35] the detachment opened the battle in the early dawn by clashing with Union pickets.

[37] The felled trees slowed Fagan's main attack,[38] which was on the Upper Little Rock Road,[39] and forced the Confederates to leave their supply wagons and cannons behind.

[38] Either at 3:30 am[29] or shortly after 4:00 am, Fort Curtis fired a warning shot, alerting the Union defenders to the Confederate approach.

[43] Meanwhile, on the Lower Little Rock Road, Brooks ran into trouble, taking fire from Battery K, 1st Missouri Light Artillery Regiment and Tyler.

[55] Walker's men spent the rest of the morning primarily skirmishing with Clayton's cavalry and firing at long range.

[50] Price's command consisted of the brigades of Brigadier Generals Dandridge McRae and Mosby Monroe Parsons, and was led by the 9th Missouri Sharpshooter Battalion and a company of Arkansans local to the Helena area.

[67] A critical moment in the battle had arrived: if the Confederates could get enough artillery onto Graveyard Hill, they could shell the Union forces into submission.

[69] Believing a full-fledged attack to be a suicide charge, McRae had his men simply fire on the rifle pits in hopes of diverting attention away from Fagan's command.

After Marmaduke's withdrawal, Union troops attempted to attack Walker's flank, but the Confederate cavalrymen withdrew from the field before they were caught.

[88] The unit had not completed formation at the time of the battle and was poorly trained, so it had been positioned in an area where it was unlikely to be directly engaged.

[96] Most of the Confederates withdrew from the area the next morning,[97] falling back to Jacksonport,[59] although Walker's men remained behind to harass any Union troops that sallied forth from the city.

Believing that the Confederates were preparing to attack again, Prentiss requested reinforcements, which arrived from Memphis, Tennessee, on July 6.