[2] The county was historically significant early in the 19th century as a conduit for settlement of the Northwest Territory, and again in the early 20th century as an automotive manufacturing center, but has been in economic decline since the 1960s and is now among the poorest counties in the state.

The county lacks a commercial airport and bus service, and has no major (U.S. or Interstate) highways.

The county and its seat Connersville rose from unincorporated territory surrounding an isolated trading post on the Whitewater River to the principal conduit for settlement of northern and central Indiana, Michigan, Wisconsin and Illinois during the early 19th century, to an automotive manufacturing powerhouse in the first half of the 20th century, suffered recession and post-war industrial revival before declining to one of the poorest counties in Indiana and the central midwest.

After early settlement, during industrial growth, the county's population concentrated in the town of Connersville.

Nomadic Miami, Shawnee, and Potawatomi peoples inhabited the area when European explorers arrived and began to form settlements, between the 1670s and early 1800s, and were in the area for at least two hundred years prior to the earliest European explorers.

The Delaware Indians, displaced from their ancestral homelands in the east, would later migrate to the Whitewater Valley.

By the Ohio Enabling Act of 1802 settlers in the Whitewater valley became citizens of the Indiana Territory and residents of Clark county, which had been organized from the eastern part of Knox in 1801, with the county seat at Falls of the Ohio, later called Clarksville.

[4] On September 30, 1809, the United States, on behalf of the Northwest Territory and Governor William Henry Harrison, concluded the Treaty of Fort Wayne, part of whose terms included the purchase from the Indians of a strip of land locally called "The 12 Mile Purchase" parallel to and west of "The Gore", enclosing the Whitewater Valley and comprising the largest portion of the future county.

Conclusion of the treaty essentially ended Indian occupation of the county and cleared the way for settlement.

It was named for the Marquis de la Fayette, a French hero of the Revolutionary War.

[6][7] Connersville, then a small village of less than a hundred inhabitants, was designated the county seat.

The far eastern part of Fayette lying between the Treaty of Greenville treaty line of 1795 and the present eastern boundary line of Waterloo and Jennings townships was split off into the newly created Union County in 1821.

Four additional townships were created in later years: Posey (1823), Orange (1822), Jackson (1820) and Fairview (1851), corresponding to settlement of the area.

Two major events spurred early growth: the completion of the Whitewater Canal in 1847, and the arrival of the Cincinnati, Hamilton and Indianapolis Railroad through Connersville in 1862.

Economic productivity in the county, except for farming, has been centered almost exclusively in the one town of Connersville.

Connersville also was home to suppliers, including Central Manufacturing, which made bodywork for the 1940 Packard Darrin, along with some 500,000 Jeep bodies during World War II.

The county (and all of Indiana) is part of the Eastern (U.S.) Broadleaf Forest biome dominated by deciduous trees including over 175 native species of oak.

Three major state roads all pass through Connersville: There is no commercial airport or bus service in the county.

Most of the economic activity is local manufacturing, retail trade and healthcare services, concentrated in Connersville.

The commissioners are charged with executing the acts legislated by the council, collecting revenue, and managing the day-to-day functions of the county government.

The judge on the court is elected to a term of four years and must be a member of the Indiana Bar Association.

Each of these elected officers serves a term of four years and oversees a different part of county government.

[21] As of the 2010 United States Census, there were 24,277 people, 9,719 households, and 6,669 families residing in the county.