Native Americans had once inhabited a large late historic village in Petersburg that contained "at least two periods of habitation dating to 1150 A.D. and 1400 A.D."[5] In 1729, an unknown Frenchman sketched an area on his chart at what is now Big Bone Lick State Park with a note that it was "where they found the bones of an elephant.

"[5] Another Frenchman, Charles le Moyne de Longueuil (1687–1755), would later be credited with being the first to investigate the Big Bone Lick area.

[5] In 1789, 10-year-old John Tanner was captured by Ojibwe Indians across from the mouth of the Great Miami River, while his Baptist minister father, brother, and their slaves were planting corn.

The group crossed the ice just west of Covington, Kentucky at daybreak, and escaped to Cincinnati, then divided to avoid detection.

[6] Margaret Garner would become famous for slitting her own daughter's throat (Mary) to prevent her from going back into slavery when Archibald K. Gaines and his posse, along with Federal Marshals, caught up to the fleeing slaves at Joseph Kite's house.

[6] Margaret Garner was first owned by, and may have been the daughter of, the plantation owner John Pollard Gaines himself.

[9] Margaret Garner's story was the inspiration for the novel Beloved (1987) by Nobel Prize winner Toni Morrison (that later was adapted into a film of the same name starring Oprah Winfrey), as well as for her libretto for the early 21st century opera Margaret Garner (2005), composed by Richard Danielpour.

In 1976, however, the county gave exactly the same number of votes to Democrat Jimmy Carter and Republican Gerald Ford.

The Main Jail has the capacity of housing 424 maximum, medium, and minimum security inmates.

[20] Boone County is the location of the Cincinnati/Northern Kentucky International Airport, which includes the headquarters of DHL Express and Southern Air.

The Creation Museum (Petersburg), operated by the apologetics ministry Answers in Genesis, as well as Big Bone Lick State Park, "birthplace of American paleontology", Jane´s Saddlebag and Boone County Arboretum are located in Boone County.