He helped build a ship that was sailed to California to exchange for cattle, and voted at the May 2, 1843, Champoeg Meeting.
[1] During this time he helped build the Star of Oregon along with Felix Hathaway, John Canan, Ralph Kilbourne, Henry Woods, George Davis, Jacob Green, and later Joseph Gale.
[2] The ship was then sailed to California where it was sold in a three-way deal where the Oregon pioneers received cattle.
[2] Armstrong and the others then drove 1,250 head of cattle, 600 horses and mules, and 3,000 sheep overland back to Oregon, arriving in early 1843.
[2] On May 2, 1843, Pleasant Armstrong attended the meetings held at Champoeg, Oregon, where the pioneer settlers voted on whether to form a government.