The borderlands of Kansas and Missouri were battlegrounds for insurgents during the American Civil War, with raids going back and forth across the border. 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.
The Kansas soldiers were badly outnumbered but stood their ground, fighting valiantly. The skirmish was covered by The New York Times, which noted the men's bravery at a time when many people questioned whether former slaves could make good soldiers. 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. This was done under Order No. 11. The county had been a base of Confederate guerrillas. But, Ewing's order generated outrage and added to support of guerrillas in some areas.
This mostly rural county continued to support agriculture in the decades after the Civil War and continues in the 21st century.
The above information is from Wikipedia. If you are interested in more history about the county, we recommend visiting the Bates County Museum.