Formed January 29, 1841 (74th county)
Oregon County (8,641), Alton (705), Thayer (1,881)
The red brick Art Deco courthouse was built in 1939 and enlarged in 1996. The facility is on Main Street at Pine Street. United States Highway 160 passes one block to the east. Earl Hawkins is the building architect. There were 1847, 1861, and 1871 courthouses earlier. The county was created on January 29, 1841 from Ripley County as the 74th county. Thomasville was the first county seat until 1860 when Alton became the county seat. The county is named for the Oregon Territory. It is also the source name for the county seat of Holt County. The county seat is named for Alton, Illinois.
Oregon County government consists of a sheriff, an administrator, an attorney, a collector, a coroner, an assessor and a clerk (executive). It has 3 Commissioners (legislative.) One Circuit Court Judge serves Oregon, Carter, Howell, and Shannon counties and One County Court Judge and a court clerk serve Oregon County (judicial.) The county is on the southern border with Arkansas. Saint Louis, Missouri is northeast and Springfield, Missouri is northwest of the county. The county center is 2.9 miles West of Alton. The county is surrounded clockwise by Shannon, Carter, and Ripley counties and Arkansas and Howell County.
The area of the county is 792 square miles. It is 15 out of 115 in the state. It ranks 92 out of 115 in population in the state. It has a density of 10.9 persons per square mile making it 103 out of 115 in the state. Oregon County has 32.2% of its population in its incorporated areas. United States Highway 63 clips the southwest corner of the county from Howell County, west, to Arkansas, south. United States Highway 160 passes east to west from Ripley County to Howell County. Oregon County is an overall rectangle with the northeast corner missing. Alton is located near the center of the county. Thayer is at the southwest border of the county. Alton is the county seat and Thayer is the largest city. Alton is 8.2% of the county population while Thayer is 21.8% of the county population.
Alton
Koshkonong
Thayer
