The 8th Maine was mustered into service for a three-year enlistment on September 7, 1861. About 1,586 men served in the 8th Maine; of these, 134 were killed in action or died of their wounds; 355 men were wounded; another 247 died of various diseases while in the service, and 35 men perished in Confederate prisoner-of-war camps.

They served in the following engagements:

• Fort Pulaski, GA - April 10-11, 1862
• Jacksonville, FL - March 23-31, 1863
• Drewry's Bluff, VA - May 4-16, 1864
• Ware Bottom Church, VA - May 9-20, 1864
• Cold Harbor, VA - May 31 -June 12, 1864
• Petersburg, VA - July 30, 1864
• Chaffins Farm, VA - September 28-30, 1864
• Fort Gregg, VA - April 2, 1865
• Fort Baldwin, VA - April 2, 1865
• Rices Station, VA - April 6, 1865
• Appomattox, VA - April 9, 1865