JEFFERSON COUNTY, MISSOURI Jefferson County was separated from St. Louis and St. Genevieve Counties and established in 1818. Named after Thomas Jefferson, the county covers 656.8 square miles and has a
population of 198,099. As of the November, 2000 general election there were 129,889 registered voters in  Jefferson County comprising 90.9% of the voting age population. There were 71,499 households in the county with an average size of 2.74 persons and the median age of residents was 34.9 years.
Median household income was $46,338 annually with 5.0% of county families and 6.8% of the total population with incomes below the poverty level. 84.3% of workers drove to work alone and .2% took public transportation to work. The county is governed by a three member County Commission led by the Presiding Commissioner and has 13 municipalities. While urbanization in the northern part of Jefferson County and within
municipal fringe areas has been increasing, much of the remainder of the county retains its rural, small town character.. | 
