Marion County was created by the Provisional Legislature of Oregon on July 5, 1843 as the Champooick
 District, one of the  original four districts of the Oregon Country along with Twality (later Washington),
 Clackamas, and Yamhill counties. The  four districts were redesignated as counties in 1845.

 Originally, this political entity stretched southward to the California border and eastward to the Rocky
 Mountains. With the creation  of Wasco, Linn, Polk, and other counties, its area was reduced in size. Marion
 County's present geographical  boundaries were established in 1856.

 In 1849, Salem was designated the county seat. The territorial capital was moved from Oregon City to
 Salem in 1852. The ensuing controversy over the location of the capital was settled in 1864 when Salem
 was confirmed as the state capital.