Polk County (named in honor of 11th president James Polk) was founded in 1845 by the Oregon Provisional Legislature, the precursor to the Oregon Territory. It occupies the west bank of the WillametteRiver at Salem and stretches westward into the Coastal Range, and is home to Laurel Mountain, the 4th highest peak in the CR and the wettest place in Oregon.
Politically, it is a counterbalance, leaning slightly Republican like much of Eastern Oregon across the fulcrum of the heavily blue I-5 corridor from Eugene to Portland. The current population is a little over 75,000 and has shown population growth in every census taken since 1860. It is overwhelmingly white (89%), and married (57%). It is predominantly rural and agricultural, with a median income of just over $42,000. Just .42% of its area is water, and it is strongly delineated between east and west, the eastern half of the roughly square 744 sq. mile county being mostly river-delta farmland, while the western half is heavily forested foothills of the CR. The county seat is Dallas (named for Polk's VP George Dallas), formerly known as Cynthian (or Cynthia Ann), a settlement along Rickreall Creek.
It is host to the Baskett Slough National Wildlife Refuge and a portion of the Siuslaw National Forest. It is home to 29 places on the NationalHistoric Register, including the former site of Fort Yamhill, an antebellum military outpost boasting Civil War generals Phil Sheridan, Joseph Hooker, and Joseph Wheeler among its roll call. The original blockhouse can still be seen in the town square of Dayton.