[1] Col. Webster began recruiting in April 1861 shortly after the attack on Fort Sumter.

[1] On July 19, 1861, the regiment was reviewed by Governor John Albion Andrew on Boston Common and presented with its colors.

[3] The regiment was first assigned to the Army of the Shenandoah under the command of Major General Nathaniel P. Banks.

Until the spring of 1862, the regiment was employed in uneventful picket duty in the vicinity of Frederick, Maryland.

[4] In late February, the 12th Massachusetts, as part of Brigadier General John Abercrombie's brigade, moved into Virginia.