Polk County History
The Provisional Legislature created Polk County from Yamhill District on Dec. 22, 1845. The county was named after President James Knox Polk and originally included the entire southwest portion of present day Oregon to the California border. County boundaries were periodically changed to reflect the creation of Benton and Lincoln Counties. Polk County today contains 745 square miles and stretches from the Willamette River on the east to the Coast Range on the west. It is bordered by Yamhill, Lincoln, Benton, and Marion Counties.
The first county seat was a settlement on the north side of Rickreall Creek named Cynthian (also known as Cynthia Ann). In 1852 city officials changed the name to Dallas after Vice President George M. Dallas. By 1856, the lack of an adequate source of drinking water compelled the town to move more than a mile to the south. During the 1880s and 1890s, Dallas withstood efforts to move the county seat to nearby Independence.
Three courthouses have served Polk County. The first was built in Cynthian in 1851 but was dismantled when the town was moved. Soon after the county built a second courthouse in Dallas, but it was destroyed by fire in 1898. Construction of the present courthouse began the same year and was completed in 1900. In 1966 the county completed a three-story annex. Further expansion occurred in 1989 when the Polk County Human Services Department was consolidated in the newly acquired Academy Building.
For over a century, Polk County was governed by a county court. By the early 1960s the county court had ceased to exercise judicial power and was renamed the board of commissioners. The board of commissioners acts as the governing body for the county and is responsible for county administration, management, and policy. Polk County's 2011 population of 75,965 represented an increase of more than 20% over the 2000 population of 62,380.
The major industries of the county are agriculture, forest products, manufacturing, and education. Western Oregon University is located in Monmouth.
Inside Polk Courthouse