Nicholas Greusel (July 4, 1817 – April 25, 1896) commanded the 36th Illinois Infantry Regiment during the early part of the American Civil War.

The regiment served under James Bankhead's command in the area around Orizaba and Córdoba, skirmishing with guerillas and small groups of Mexican regulars.

By good management of company funds, Greusel saved $300 which he used to buy new shirts and shoes for his soldiers.

[3] On April 18, 1861, after the Battle of Fort Sumter, Captain Greusel enrolled the Aurora Company in the Illinois militia for three-months service.

On August 14, Governor Richard Yates appointed Greusel colonel of the "Fox River Regiment".

[6] At the Battle of Pea Ridge on March 7–8, 1862, Greusel commanded the 2nd Brigade in the 1st Division under Peter Joseph Osterhaus.

He ordered Osterhaus to march to Leetown with some cavalry units and Greusel to follow with his brigade and elements of the 3rd Division.

The soldiers did not panic and Osterhaus arrived to find Greusel calmly directing the deployment of the troops along the southern edge of Oberson's field.

When the 6th Texas Cavalry Regiment suddenly burst into Oberson's field, it was quickly taken under fire and compelled to retreat.

[9] Greusel ordered the gunners to lob howitzer shells over the woods and this blind fire proved surprisingly effective, panicking the Confederates' Indian allies.

The loss of two leading generals led to a disastrous breakdown in the chain of command and "doomed the Confederate effort at Leetown" that day.

That morning Franz Sigel organized a highly effective bombardment by 21 guns on the Union left flank.

[14] At the Battle of Perryville on October 8, 1862, Greusel commanded the 37th Brigade in Philip Sheridan's 11th Division, Charles Champion Gilbert's III Corps, Don Carlos Buell's Army of the Ohio.

[16] On the late afternoon of October 7, Greusel's brigade was committed to help the Federal cavalrymen, causing the Confederate horsemen under Joseph Wheeler to pull back.

[17] At 4:00 pm on October 8, three Confederate regiments launched an ill-considered attack on Sheridan's division perched on Peters Hill.

[18] At the Battle of Stones River on December 31, 1862–January 2, 1863, Greusel commanded the 36th Illinois in Joshua W. Sill's 1st Brigade, Sheridan's 3rd Division, Alexander McDowell McCook's Right Wing, William Rosecrans's Army of the Cumberland.

[19] An hour after the Confederates attacked McCook's right flank on the morning of December 31, five Union brigades were fleeing in confusion or panic.

During the first clash, Sill was shot dead and Greusel assumed leadership of the brigade, with Silas Miller taking command of the 36th Illinois.

[23] Taking up a third position, Sheridan swung Greusel's brigade back to the Blanton house where the 24th Wisconsin had rallied.

This badly-timed command resulted in the Confederate seizure of six guns from Charles Houghtaling's Battery C, 1st Illinois Light Artillery.

One source stated that Greusel was breveted brigadier general after Stones River by the recommendation of William Rosecrans.

After the war was over, on October 15, 1865, Sheridan wrote a highly complimentary letter to Greusel, thanking him for his services.

[3] After leaving the army, Greusel resumed his employment as a conductor with the Chicago, Burlington and Quincy Railroad.

[2] In 1876, at the International Peace Union convention at Carpenters' Hall in Philadelphia, there was a proposal to convert swords into useful tools.