 In October 1861, the Vermont General Assembly elected Washburn to succeed Horace Henry Baxter as Adjutant General and Inspector General of the state militia with the rank of brigadier general.During his tenure, he oversaw the raising, equipping and fielding of seven infantry regiments, one cavalry regiment, three batteries of light artillery, and two companies of sharpshooters for the Union Army.Washburn also took charge of Vermont's response following the October 1864 St. Albans Raid by Confederate soldiers based in Canada.