[4] This mostly rural county has an overwhelmingly ethnic European-American population, which has declined in number since the early 20th century as people have moved to cities.

Bates County is noted as the site for the first combat engagement during the war of African-American soldiers serving with the Union and against Confederate forces, which occurred on October 28–29, 1862.

The First Kansas Colored Division (part of the state militia) fought Confederate guerrillas at the Battle of Island Mound four miles north of present-day Rich Hill, Missouri, and the Union forces won.

[5] Their heroic action preceded President Abraham Lincoln's announcement of the Emancipation Proclamation in January 1863 and establishment of the United States Colored Troops.

Following a massacre of men and boys and the burning of Lawrence, Kansas, by Confederate bushwhackers in the summer of 1863, the United States General Ewing ordered the evacuation of the civilian population from rural areas of Bates and nearby counties except for within a mile of certain Union-controlled cities, in order to cut off sources of support for Confederate insurgents.

Bates County, along with the rest of the state of Missouri, is represented in the U.S. Senate by Josh Hawley (R-Columbia) and Roy Blunt (R-Strafford).

Like most rural areas throughout Missouri, voters in Bates County generally adhere to socially and culturally conservative principles which tend to influence their Republican leanings, at least on the state and national levels.

On the Democratic side, former Vice President Joe Biden (D-Delaware) both won statewide and carried Bates County by a wide margin.

Incumbent President Donald Trump (R-Florida) faced a primary challenge from former Massachusetts Governor Bill Weld, but won both Bates County and statewide by overwhelming margins.

Businessman Donald Trump (R-New York) narrowly won the state overall and carried a plurality of the vote in Bates County.

Senator Rick Santorum (R-Pennsylvania), who finished first in the state at large, but eventually lost the nomination to former Governor Mitt Romney (R-Massachusetts).

In 2008, the Missouri Republican Presidential Primary was closely contested, with Senator John McCain (R-Arizona) prevailing and eventually winning the nomination.

Then-Senator Hillary Clinton (D-New York) received more votes than any candidate from either party in Bates County during the 2008 presidential primary.

Despite initial reports that Clinton had won Missouri, Barack Obama (D-Illinois), also a Senator at the time, narrowly defeated her statewide and later became that year's Democratic nominee, going on to win the presidency.