On 8 January 1864, most of the soldiers of the 33rd Illinois reenlisted as veterans; a bounty of $402 was offered. The men who chose to reenlist left Texas on 28 January 1864 while those who chose not to reenlist were transferred to the 99th Illinois Infantry Regiment. The men who reenlisted reached Bloomington on 14 March and received their veterans' furlough. On 18 April, the regiment reorganized at Camp Butler and proceeded first to St. Louis and then to New Orleans, arriving on 29 April. The unit moved to Brashear City on 17 May where it was parceled out to defend the railroad. Companies A and D were ordered to Tigerville, Company B to Bayou Lafourche, Companies C, F, and K to Bayou Boeuf, Company E to Terre Bonne, Company G to Chacahoula, Company H to Boutte, and Company I to Bayou L'Ourse. The unit was assigned to the District of LaFourche in June 1864 – February 1865. The men temporarily assigned to the 99th Illinois rejoined the 33rd Illinois on 3 July 1864.