Clinton County was founded in 1810 and was named in honor of George Clinton who was vice-president at the time of the U.S. Settlers. Clinton had been a delegate to the second Continental Congress. They named the county seat Wilmington, derived from the seaport in North Carolina. Fear of the Indians had retarded emigration to that date, and, although the lands had been surveyed to a great extent, and warrants were held for nearly all the land in the Virginia Military District, no steps had yet been taken toward their settlement. In September, 1705, a month after the treaty of Greenville, a block-house was erected and a settlement begun at Bedle's Station (this name is variously spelled, being given Bedell perhaps as often as any other way, but Warren County authority settles upon the spelling as first above),

Morgan Van Meter came to Clinton County as early as 1798 or 1799 and was the first settler. It is believed that he was settled at Deerfield, Warren County, with his brothers, Joseph and Isaac, as early as 1796, or at least 1797, having come here from Harrison County, Ky. The first division of Clinton County into townships occurred at a meeting of the Commissioners of the county held April 6, 1810. At this meeting were present George McManis, James Birdsall and Henry Babb, Commissioners.

Clinton County proved a continuing headache to the legislature. The Ohio Constitution requires that every county have an area of at least four hundred square miles (1,036 km²). Clinton County's boundaries were several times adjusted in an effort to comply with that clause of the constitution. One of them, the Act of January 30, 1815, detached a strip of land from the eastern side to give to Clinton. That would have left Warren under four hundred square miles (1,036 km²), so a portion of Butler County (the part of Franklin Township where Carlisle is now located) was attached to Warren in compensation. Finally, the townships where divided into fourteen townships and they are as follows: Wilmington, Union, Adams, Chester, Clark, Greene, Jefferson, Liberty, Marion, Richland, Vernon, Washington, Wayne, and Wilson

The county is essentially a rural one and is still known for its corn and hog production. The main industries include; metals, printing and publishing, machinery, plumbing castings, gears, bits and automotive tools. Hogs are the agricultural product.Landmarks such as the Murphy Theatre, the General Denver Hotel, the Clinton County Courthouse, the Snow Hill Country Club and General James W. Denver’s former residence, home of the Clinton County Historical Society Museum, preserve the county’s history.”