On February 28, 1862, Brigadier General J. C. Tappan, formerly commander of the 13th Arkansas Infantry Regiment, was ordered to assume command of Shaver's brigade, consisting of the 38th Arkansas Infantry Regiment, commanded by Colonel Robert G. Shaver, the 27th Arkansas Infantry Regiment commanded by Colonel James R. Shaler, and the 33rd Arkansas Infantry Regiment commanded by Colonel Hiram L. Grinstead. They remained with Tappan's Brigade through the remainder of the war.

In the Summer of 1863 General Tappan was ordered to move his brigade to Louisiana to support General Taylor's operations against General's Grant's forces laying siege to Vicksburg Mississippi. The 33rd spent the month of July 1863 in the vicinity of Delhi, Louisiana where they conducted raids on Federal interests between Delhi and the Mississippi River. Tappan's Brigade and the 33rd Arkansas missed the Battle of Helena on July 4, 1863, because of its operations in Louisiana.

Tappan's brigade was ordered to return to Arkansas, via Pine Bluff, in August 1863. Tappan's Brigade and the 33rd returned to Arkansas in August 1863, and were involved in the defense of Little Rock. When Little Rock fell on September 10, 1863, the regiment withdrew to southern Arkansas and went into winter quarters in Hempstead County.

In the Spring of 1864, Churchill's Division, with Tappan's Brigade moved south to oppose Union General Nathaniel Banks' Red River Campaign in north-central Louisiana in March and early April 1864. The division arrived during the Battle of Mansfield on April 8, 1864, but was not committed to the battle and occupied a position on the flank of General Taylor's division. Brigadier General Churchill was placed in command of both his own division and Brigadier General Parson's Division during the pursuit of the enemy from Mansfield to Pleasant Hill, Louisiana so Brigadier General Tappan assumed command of Churchill's Division. While Tappan commanded the Division, Colonel Grinstead assumed command of Tappan's Brigade and led it through the fight at Pleasant Hill, on April 9, 1864.

https://en.wikipedia.org/wiki/33rd_Arkansas_Infantry_Regiment

United States. War Dept. The War of the Rebellion: A Compilation of the Official Records of the Union And Confederate Armies. Series 1, Volume 22, In Two Parts. Part 2, Correspondence., Book, 1888; digital images, (http://texashistory.unt.edu/ark:/67531/metapth154590/m1/857/?q=Tappan : accessed July 02, 2012), University of North Texas Libraries, The Portal to Texas History, http://texashistory.unt.edu; crediting UNT Libraries, Denton, Texas

United States. War Dept. The War of the Rebellion: A Compilation of the Official Records of the Union And Confederate Armies. Series 1, Volume 22, In Two Parts. Part 2, Correspondence., Book, 1888; digital images, (http://texashistory.unt.edu/ark:/67531/metapth154590/m1/951/?q=Tappan : accessed July 02, 2012), University of North Texas Libraries, The Portal to Texas History, http://texashistory.unt.edu; crediting UNT Libraries, Denton, Texas.