The 25th Connecticut Infantry Regiment was an infantry regiment that served in the Union Army during the American Civil War for nine months service.
The 25th Connecticut Infantry Regiment was organized at Hartford, Connecticut, on November 11, 1862, under the command of Colonel George P. Bissell.
The regiment was attached to Grover's Division, Department of the Gulf, to January 1863. 3rd Brigade, 4th Division, XIX Corps, Department of the Gulf, to August 1863.
The 25th Connecticut Infantry mustered out of service August 26, 1863.
Left Connecticut for eastern New York November 14, then sailed for New Orleans and Baton Rouge, La., November 29, arriving there December 17. Duty at Baton Rouge until March 1863. Operations against Port Hudson March 7-27. Moved to Donaldsonville March 28. Operations in western Louisiana April 9-May 14. Bayou Teche Campaign April 11-20. Porter's and McWilliams' Plantation at Indian Bend April 13. Irish Bend April 14. Bayou Vermillion April 17. Expedition to Alexandria and Simsport May 5-18. Moved to Bayou Sara, then to Port Hudson May 22-25. Siege of Port Hudson May 25-July 9. Assaults on Port Hudson May 27 and June 14. Surrender of Port Hudson July 9. Moved to Donaldsonville July 11. Duty in Plaquemine District until August.
The regiment lost a total of 94 men during service; 3 officers and 26 enlisted men killed or mortally wounded, 4 officers and 61 enlisted men died of disease.
- Colonel George P. Bissell
- Lieutenant Colonel Mason C. Weld - commanded during the siege of Port Hudson
- Dyer, Frederick H. A Compendium of the War of the Rebellion (Des Moines, IA: Dyer Pub. Co.), 1908.
- Bissell, George P. The Twenty-Fifth Regiment Connecticut Volunteers in the War of the Rebellion: History, Reminiscences, Description of Battle of Irish Bend, Carrying of Pay Roll, Roster (Rockville, CT: Rockville Journal), 1913.
- McManus, Thomas. Battle of Irish Bend: Interesting Reminiscences of That Terrible Combat / An Address Given Before the People of St. Patrick's Church, Collinsville, April 23, 1891 (S.l.: s.n.), 1891.
- McManus, Thomas. Battle Fields of Louisiana Revisited a Second Time (Hartford, CT: The Fowler & Miller Co.), 1898.
- McManus, Thomas. Through the Campaigning Grounds of Louisiana (S.l.: s.n.), 1907.
- McManus, Thomas. Twenty-Fifth Regiment: Battle Fields Revisited (Hartford, CT: Clark & Smith), 1896.
- This article contains text from a text now in the public domain: Dyer, Frederick H. (1908). A Compendium of the War of the Rebellion. Des Moines, IA: Dyer Publishing Co.