Was recruited under the President's proclamation of 22 Jul 1861, and rendezvoused at Camp McClellan, near Davenport. There were 989 men on the rolls. Maj. M. M. Crocker, of the 2nd Regt. was commissioned Colonel.

From 20 Nov to 11 Dec., the regiment remained at Benton Barracks, and was assigned to garrison duty at Jefferson City during the Winter. In March Col. Crocker received orders to report to Gen. Grant; and on the 8th of that month, 1862, the regiment left, by railroad, for St. Louis where it embarked for Pittsburg Landing, arriving on the 23rd. Col. Crocker reported to Gen McClernanl, commanding 1st Division, and with the Eleventh Iowa and Eighth and Eighteenth Illinois, constituted the First Brigade, under Col. Richard Oglesby.

At Shiloh, on the first day it was under fire for ten consecutive hours, and gallantly sustained the reputation of Iowa troops. On that day, Lt. Col. Price and Major Shane were wounded, and the regiment lost 24 killed, 139 wounded, and 9 missing. A few days after the battle of Shiloh the army was re-organized, and the Thirteenth was placed in the Sixth Division, attached to the Third Brigade, composed of the eleventh, Thirteenth, Fifteenth and Sixteenth Iowa Regiments, Col. Crocker commanding, soon becoming known as the "Iowa Brigade."About this time, Lt. Col. Price resigned, Maj. Shane was promoted to be Lt. Col., and Capt. G. M. became Major. The command participated in the siege of Corinth, and became a part of the garrison at that place when evacuated by the rebel force.

After remaining at Corinth two months, the regiment marched to Bolivar, TN, to look after the enemy, but returned to Corinth 12 Sept.

Its next movement was under Gen. Ord, in a march on Iuka, and returned to Corinth about the 1st of Oct., where it was engaged on the 3rd and 4th; but although under heavy artillery fire for some time, its losses were light. On Sunday morning, 5 Oct, the command joined in pursuit of the rebels, which was continued to Ripley. On its return, the regiment reach Corinth 11 Oct., where it remained three weeks, when it joined in a campaign under Gen. Grant against Vicksburg, via Holly Springs, and Granada. It reached Yocana Creek, when, Holly Springs being lost, the army counter marched to the frontier of Tennessee, and arrived at Memphis 13 Jan 1863. On the 20th, it embarked on steamers, moving down the river to Duckport, LA; but, without disembarking, returned to Milliken's Bend where it remained a fortnight. It then moved to Providence and went into camp for two months working much of the time on the Lake Providence Canal. While here the army was re-organized and the Thirteenth became a part of the First Division, Seventeenth Corps, observation, Gen. McPherson commanding. Shortly after, Col. Crocker was promoted to be a Brigadier General, when Lt. Col. Shane was commissioned Colonel of the regiment.

In August, it was engaged with a portion of the navy in wrecking and dismantling gunboats that had been sunk by rebel torpedoes at Yazoo River. It also participated in a campaign against Monroe, LA, under Gen. Stevenson. 3 Sept. it went into quarters at Vicksburg, where it remained forfour months. From 4 Feb. to 4 Mar., 1864, it was with the forces under Gen. Sherman in the famous raid on Meredian. On its return from this raid, most of the men having re-enlisted, it was declared a veteran organization, and officers and men were given "thirty days in their own state", and were homeward bound on the 7th of March.

16th April, there were off to the wars again, arriving at Huntsville, AL, 20 May, thence to Acksorth, GA, joining Sherman's army on the 8th of June. Its first battle in the Atlanta campaign was at Kenesaw Mountain, and was almost continuously under fire until 20th July, when it took position, before Atlanta, three miles away.On the 21st, the Iowa Brigade, under Col. Shane lost 226 men in twenty-seven minutes, in a splendid assault on a rebel fort. Again engaged on the 22nd and suffered severely. On the 28th, gallantly fought, having been ordered to reinforce a portion of the line hard pressed by the enemy.

It participated in Sherman's famous march to the sea, and a portion of the regiment, under Lt. Col. Kennedy, entered Columbia and hoisted the Stars and Stripes on the rebel capitol.

The Thirteenth, after a long and honorable career was mustered out, paid off and disbanded at Davenport, IA, 28 and 29 Jul 1865.