Late in that month, the regiment was sent to Washington, D.C., and initially assigned to Hatch's cavalry brigade in Nathaniel Banks' V Corps in the Department of the Shenandoah.

Throughout the war, the regiment would be a part of many reorganizations of the cavalry, although the majority of its service was with the Army of the Potomac.

Shortly thereafter, isolated and alone deep in Confederate territory on a scouting mission, they lost nearly 240 of their 280 remaining men at the June 17 skirmish at Middleburg.

The following year, the 1st Rhode Island served in the defenses of Washington, D.C., before eventually returning to the Shenandoah Valley under the command of Philip H. Sheridan.

Due to heavy battle losses, the regiment was consolidated to a battalion of four companies on January 1, 1865.