With the fall of Fort Sumter, President Lincoln called for the formation of an army of 75,000 three-month men. This proclamation had a serious effect on the officers and men of the Department of the Pacific. They were required to proceed to Washington City. In their places, the Governor raised an armed force of men from the states of California and Oregon and from the Washington Territory called the 1st Washington Territory Infantry.

The chronology of events can be seen below:

April 25, 1861 - General Order #5 - Department of the Pacific commanded by Brigadier General Edwin V. Sumner when Brigadier General Albert Sydney Johnson resigned.

May 1861 - Acting Governor Henry M. McGill received the Proclamation from President Lincoln calling for 75,000 soldiers.

May 10, 1861 - Acting Governor McGill issued a Proclamation that called for the formation of a territorial militia.

May 14, 1861 - Adjutant General Franklin Matthias issued a General Order to facilitate the enrollment of the territorial militia.

June 11, 1861 - Colonel Wright issued Special Order #9 closing some forts, reinforcing others and moving men and materiel…some to the Eastern theater and others in defense of Oregon and Washington.

June 21, 1861 - Colonel Wright reminded his previous order to abandon Camp Pickett based on the threat of Indians in Puget Sound.

October 18, 1861 - Colonel Justus Steinberger mustered into the U. S. Army in Washington City.

October 21, 1861
- Acting Secretary of War, Thomas A. Scott authorized Colonel Justus Steinberger to organize a regiment of infantry for Washington Territory.

December 10, 1861 - Brigadier General Lorenzo Thomas directed Colonel Steinberger to take up posting at Fort Vancouver.