 st. clair county is a county located in the western portion of the u.s. state of missouri. as of the 2010 census, the population was 9,805. its county seat is osceola. the county was organized in 1841 and named for general arthur st. clair, governor of the northwest territory. st. clair was also the 9th president of the united states in congress assembled. under his presidency, the northwest ordinance and united states constitution were passed. according to the april 1907 issue of the century magazine, for well over 30 years (dating from 1870) st. clair county was in open rebellion against the u.s. government- refusing to pay interest on bonds which it had issued to assist in the building of a railroad, which was never built. ==geography== according to the u.s. census bureau, the county has a total area of , of which  is land and  (4.6%) is water. ===adjacent counties=== *henry county (north) *benton county (northeast) *hickory county (east) *polk county (southeast) *cedar county (south) *vernon county (southwest) *bates county (northwest) ===major highways=== *[[imag
1841_establishments_in_Missouri Missouri_counties Populated_places_established_in_1841