Grant County, once a part of Pendleton County, became an independent County in 1820.  The bill for the formation of Grant County was passed by the Kentucky legislature and was approved by the Governor on February 12, 1820.  The commissioners appointed to decide upon a permanent site for the new county seat reported that they had located the farm of William Arnold.  There were two reasons for the selection: first, there was a large natural spring, known as the Public Spring, and the other was that Mr. Arnold offered to donate a half acre of land on which to erect the public buildings.  He also agreed to furnish to the county, and to all persons purchasing lots from him, timber to build their homes for a period of three years; and enough firewood and building stone for a period of seven years.  He made this liberal offer because he was anxious for the town to be located on his land.

 The new county seat was to be called Philadelphia, but a month later, it was discovered that another town in Kentucky had that name.  The name was then changed to Williamstown for William Arnold, who might properly be called its founder.  The new court house was completed in time for the county court in December, 1821.  At this time there were only the court house, jail and three other buildings in town.  In 1822 twenty-five acres of land were condemned by Mr. Arnold for the town of Williamstown.  It was surveyed and laid off in one-fourth acre lots, and the first trustees of the town were appointed.

One of the proudest and happiest incidents in the history of Williamstown occurred in 1824.  General Marquis de Lafayette, on his way from Lexington to Cincinnati, had breakfast at the home of Mr. Arnold..  Mr. Arnold had been a captain in the revolutionary War and had been wounded at the Battle of Yorktown.  The old friends wept at their meeting.

 jtBusiness was quick to come to Williamstown, bringing with it additional cultured people.  Better taste in dress was displayed; the hunting shirt was laid aside, and shoes took the place of moccasins.  A new era had begun.  From that time on, Williamstown proved to be a good business town and a desirable place in which to live.