They were encamped on Gallop's Island in Boston Harbor until 7 October 1864 when, as a battalion, was ordered to Virginia.

They were assigned to General Benham's engineer brigade in the Army of the Potomac and were involved in erecting fortifications until 10 November, then served on picket duty until 10 December.

A sixth company had joined them on the 17th of November[1] and from 10–12 December, they were sent to hold a part of the Welden railroad near Fort Sedgewick.

The Independent Brigade being attached to the IX Corps, the 61st was called to arms, and awaited orders to move out.

Here the brigade was engaged with the Confederate breastworks outside of the forts throughout the day and into the night, until abandoned by the enemy.