According to the U.S. Census Bureau, the county has a total area of 664 square miles (1,720 km2), of which 657 square miles (1,700 km2) is land and 7.7 square miles (20 km2) (1.2%) is water.[5] The county's eastern border is the Mississippi River.
U.S. Decennial Census[7] 1790-1960[8] 1900-1990[9] 1990-2000[10] 2010-2015[1]
As of the 2010 Census Jefferson County had a population of 218,733. The reported ethnic and racial make up of the population was 95.4% non-Hispanic white, 0.8% African-American, 0.3% Native American, 0.6% Asian, 0.4% reporting some other race, 1.3% reporting two or more races and 1.6% Hispanic or Latino of any race.[11]
As of the census[12] of 2000, there were 198,099 people, 71,499 households, and 54,553 families residing in the county. The population density was 302 inhabitants per square mile (117/km2). There were 75,586 housing units at an average density of 115 per square mile (44/km²). The racial makeup of the county was 97.48% White, 0.68% Black or African American, 0.29% Native American, 0.36% Asian, 0.01% Pacific Islander, 0.24% from other races, and 0.93% from two or more races. Approximately 1.01% of the population were Hispanic or Latino of any race.
There were 71,499 households out of which 38.90% had children under the age of 18 living with them, 61.00% were married couples living together, 10.40% had a female householder with no husband present, and 23.70% were non-families. 18.90% of all households were made up of individuals and 6.10% had someone living alone who was 65 years of age or older. The average household size was 2.74 and the average family size was 3.12.
In the county, the population was spread out with 27.90% under the age of 18, 8.50% from 18 to 24, 31.80% from 25 to 44, 22.50% from 45 to 64, and 9.20% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 98.90 males. For every 100 females age 18 and over, there were 95.90 males.
The median income for a household in the county was $60,636, and the median income for a family was $66,697. Males had a median income of $37,822 versus $25,440 for females. The per capita income for the county was $25,058. About 4.90% of families and 6.80% of the population were below the poverty line, including 8.10% of those under age 18 and 6.30% of those age 65 or over.
There were 146,316 registered voters in 2008.[13] As of Oct. 24, 2012, there were 148,011.[14]
Historically, the Democratic Party has controlled politics at the local level in Jefferson County. Democrats hold all but two of the elected positions in the county. However, Republicans have made gains in recent years; they hold five of seven seats on the county council.
Jefferson County is divided into seven legislative districts in the Missouri House of Representatives; six of which are held by Republicans and one held by a Democrat.
District 97 John McCaherty (R-High Ridge). Consists of Murphy and part of Arnold.
Missouri House of Representatives — District 97 — Jefferson County (2016)[20]
A predominantly suburban county, Jefferson County is fairly independent-leaning at the federal level but does have a tendency to tilt Democratic. Presidential elections in Jefferson County are almost always extremely close; George W. Bush just narrowly carried the county in 2004 by less than 600 votes and by just over a half of a percentage point. Al Gore and Barack Obama also just narrowly carried the county in 2000 and 2008, respectively. Bill Clinton, however, did manage to carry Jefferson County by double digits both times in 1992 and 1996. However, in 2012 the county swung hard to Mitt Romney, who carried it with 55 percent of the vote. In 2016 Donald Trump carried the county with 65% of the vote, the largest margin of any candidate since Lyndon Johnson in 1964.
Typical of the suburban culture in most counties throughout the country, voters in Jefferson County tend to be rather centrist on social issues but more liberal on economic issues. In 2004, Missourians voted on a constitutional amendment to define marriage as the union between a man and a woman—it overwhelmingly passed Jefferson County with 72.56 percent of the vote. The initiative passed the state with 71 percent of support from voters as Missouri became the first state to ban same-sex marriage. In 2006, Missourians voted on a constitutional amendment to fund and legalize embryonic stem cell research in the state—it narrowly passed Jefferson County with 51.85 percent voting for the measure. The initiative narrowly passed the state with 51 percent of support from voters as Missouri became one of the first states in the nation to approve embryonic stem cell research. In 2006, Missourians voted on a proposition (Proposition B) to increase the minimum wage in the state to $6.50 an hour—it passed Jefferson County with 79.90 percent of the vote. The proposition strongly passed every single county in Missouri with 78.99 percent voting in favor as the minimum wage was increased to $6.50 an hour in the state. During the same election, voters in five other states also strongly approved increases in the minimum wage.
U.S. SenatorHillary Clinton (D-New York) won Jefferson County over Senator Barack Obama (D-Illinois) with 61.32% of the vote, while Obama received 35.02% of the vote. Although he withdrew from the race, former U.S. SenatorJohn Edwards (D-North Carolina) still received 2.74% of the vote in Jefferson County. Jefferson County gave Clinton one of her strongest showings in a predominantly suburban county in the entire country.
Clinton had a large initial lead in Missouri at the beginning of the evening as the rural precincts began to report, leading several news organizations to call the state for her; however, Obama rallied from behind as the heavily African American precincts from St. Louis began to report and eventually put him over the top. In the end, Obama received 49.32 percent of the vote to Clinton’s 47.90% — a 1.42% difference. Both candidates split Missouri’s 72 delegates, as the Democratic Party utilizes proportional representation.
Hillary Rodham Clinton received more votes, a total of 19,075, than any candidate from either party in Jefferson County during the 2008 Missouri Presidential Primaries. She also received more votes than the total number of votes cast in the entire Republican Primary in Jefferson County.
^ ab"State & County QuickFacts". United States Census Bureau. Archived from the original on July 12, 2011. Retrieved September 9, 2013. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^"Find a County". National Association of Counties. Archived from the original on 2011-05-31. Retrieved 2011-06-07. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^"2010 Census Gazetteer Files". United States Census Bureau. August 22, 2012. Archived from the original on October 21, 2013. Retrieved November 16, 2014. {{cite web}}: Unknown parameter |dead-url= ignored (|url-status= suggested) (help)
^"U.S. Decennial Census". United States Census Bureau. Archived from the original on May 12, 2015. Retrieved November 16, 2014. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^"Historical Census Browser". University of Virginia Library. Archived from the original on August 16, 2012. Retrieved November 16, 2014. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^"Archived copy". Archived from the original on 2012-10-25. Retrieved 2012-10-28. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)CS1 maint: archived copy as title (link) Retrieved on Jul. 9, 2013
^Breeding, Marshall. "De Soto Public Library". Libraries.org. Archived from the original on May 10, 2018. Retrieved May 8, 2017. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^Breeding, Marshall. "Festus Public Library". Libraries.org. Archived from the original on May 10, 2018. Retrieved May 8, 2017. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^Breeding, Marshall. "Herculaneum Public Library". Libraries.org. Archived from the original on May 10, 2018. Retrieved May 8, 2017. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^"June 4, 2013 Special Election"(PDF). Jefferson County Clerk. June 4, 2013. Archived from the original(PDF) on September 10, 2015. Retrieved March 31, 2016. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)