The 3rd Iowa Infantry was organized at
Keokuk, Iowa and mustered into Federal forces on June 8, 1861. After moving to
Hannibal, Missouri, the regiment spent its first year guarding the
Hannibal & St. Joseph Railroad and engaging counter-guerilla operations. During this period, the regiment fought its first engagement at
Blue Mills Landing on September 17, 1861. Despite being heavily outnumbered, the 3rd Iowa conducted a fighting retreat that inflicted heavy casualties on the Confederates, though at the cost of 86 killed or wounded. In March 1862, the regiment joined
Ulysses S. Grant's army at
Pittsburg Landing, assigned to the 1st Brigade, 4th Division,
Army of the Tennessee. at the
Battle of Shiloh, the regiment held a key position on the Union left for five hours under intense fire. The regiment lost 187 men out of their 560 engaged, including its commander,
Major William M. Stone, who was captured. Following Shiloh, the regiment participated in the
Siege of Corinth and the
Battle of Hatchie's Bridge, where they famously charged across a bridge under heavy fire to dislodge Confederate forces from the heights beyond. The regiment took part in the
Siege of Vicksburg, playing a vital role there, they served on the left of the Union line until the city's surrender on July 4, 1864. Immediately following the city's fall, the regiment moved to
Jackson, Mississippi to take part in the
Siege of Jackson. On July 12, 1863, the 3rd Iowa was ordered into a disastrous frontal assault against Confederate works, where they took heavy losses, losing 114 out of their 241 engaged in just a few minutes. In 1864, for those who didn't re-enlist as veterans took part in the
Red River Campaign before being discharged, for those who re-enlisted as veterans however, joined
Sherman's Atlanta Campaign. By this time, the regiment was so depleted it was organized into a three-company battalion. During the
Battle of Atlanta, their commander, Lieutenant Colonel Jacob Abernethy, was killed. On November 4, 1864, the remaining survivors were consolidated into the
2nd Iowa Infantry. this unit would later serve in Sherman's March to the Sea and the
Grand Review of the Armies in
Washington, D.C. Before finally being mustered out on July 12, 1865. ==Total strength and casualties==