The Oregon Constitutional Convention in 1857 drafted the Oregon Constitution in preparation for the Oregon Territory to become a U.S. state. Held from mid-August through September, 60 men met in Salem, Oregon, and created the foundation for Oregon's law. The proposal passed with a vote of 35 for adoption to 10 against. Oregon then became the 33rd state of the Union on February 14, 1859.

Oregon's Territorial Legislature was a bicameral legislative body created by the United States Congress in 1848 as the legislative branch of the government of the Oregon Territory. The upper chamber Council and lower chamber House of Representatives first met in July 1849; they served as the region's legislative body until Oregon became a state in February 1859, when they were replaced by the bicameral Oregon State Legislature.