Formed January 2, 1833 (43rd county)

Warren County (35,538), Warrenton (8,443)
The Modern red brick courthouse was built in 1998. It is sited on a square at Main, Market, Walton, and West streets. Missouri State Highway M is Main Street in the city. It replaced a classier 1869 courthouse. Phillips Swager was the building architect. The courthouse features a portico on the front. There was also an 1838 courthouse in Warrenton, the only county seat. Warren County was created on January 2, 1833 from Saint Charles County as the 43rd county. The county and county seat are named for Revolutionary War hero General Joseph Warren.
Warren 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 Warren, Audrain, and Montgomery counties and One County Court Judge and a court clerk serve Warren County (judicial.) Warren County is in eastern Missouri. The Missouri River forms its southern border. Saint Louis, Missouri is east and Kansas City, Missouri is west of the county. The county center is 7.4 miles South of Warrenton. The county is surrounded clockwise by Lincoln, Saint Charles, Franklin, Gasconade, and Montgomery counties.
The area of the county is 432 square miles. It is 101 out of 115 in the state. It ranks 33 out of 115 in population in the state. It has a density of 82.3 persons per square mile making it 23 out of 115 in the state. Warren County has 45.8% of its population in its incorporated areas. Interstate Highway 70 crosses the county from east to west from Saint Charles County to Montgomery County. United States Highway 40 is joined with Interstate Highway 70 from Saint Charles to Montgomery counties. The county looks like a scoop facing south. Warrenton is located in the northeast quarter of the county. Warrenton is the county seat and the largest city. It is 23.8% of the county population. This county is in the Saint Louis Metropolitan Statistical Area.

Innsbrook
Marthasville
Pendleton
Three Creeks
Truesdale
Warrenton
Wright City
Foristell

