 After Oregon's admission to the Union as the 33rd state by act of Congress on February 14, 1859, this district was dissolved and replaced by Oregon's at-large congressional district.At the same time, the eastern portion of the territory was annexed to the Washington Territory.When the Oregon Territory was formed on August 14, 1848, Congress gave it the authority to elect a Congressional delegate, though the first delegate did not take his seat until 1849.