This is the official website for the Oregon State Archives. This site has menus for Guides, Records, and Indexes as well as Topical Research Guides for various genealogical records.
They have an online database of early Oregon residents who lived in Oregon prior to statehood through 1860.
They have an online Oregon Historical County Records guide with maps and more.
They have an online Provisional and Territorial Records Guide with several record types including maps.
They have an amazing Oregon Historical Records Index for names searches with associated genealogical and historical documents of all types.