The 2012 United States presidential election in Missouri took place on November 6, 2012, as part of the 2012 United States presidential election, in which all 50 states plus the District of Columbia participated. Missouri voters chose 10 electors to represent them in the Electoral College via a popular vote pitting incumbent Democratic President Barack Obama and his running mate, Vice President Joe Biden, against Republican challenger and former Massachusetts Governor Mitt Romney and his running mate, Congressman Paul Ryan.

Jefferson County is located in the eastern portion of the U.S. state of Missouri. It is a part of the St. Louis Metropolitan Area. As of the 2020 census, the population was 226,739, making it the sixth-most populous county in Missouri. Its county seat is Hillsboro. The county was organized in 1818 and named in honor of former president Thomas Jefferson.