The town of Moro was established in 1850, and about 700 people lived there and nearby when the Civil War began in 1861. Union troops from the 1st Indiana, 1st Missouri, 9th Illinois, 5th Kansas, 2nd Wisconsin, and 3rd and 4th Iowa Cavalry, with six cannon, camped there on the night of Nov. 7, 1862, during an expedition from Helena. After leaving the next morning, the Union command divided for the return to Helena, and bands of Confederate horsemen repeatedly struck one Union column, wounding 22 men while 15 Confederates were captured and many were killed. In late June 1863, Gen. Theophilus Holmes's Confederate army converged on Helena to attack the Union post there and relieve pressure on Vicksburg. Gen. John S. Marmaduke's cavalry and Gen. Sterling Price's infantry divisions left Jacksonport on June 22 and camped at or near Moro on June 30 after marching 69 miles on rain-soaked roads. The Confederates attacked Helena on July 4, 1863, with Marmaduke striking from the north and Price from the west, but the strongly entrenched Union garrison won the battle and inflicted 1,614 casualties.