The earliest known predecessor of the Clermont County Fair was an exhibition that took place in 1846, sponsored by the Franklin Agricultural and Horticultural Society in Monroe Township. The exhibition was mainly of farm and garden products.

The Ohio State Legislature passed laws from 1846-48 that gave organized county agricultural societies the right to draw money from the state to promote agriculture in the counties.

The Clermont County Agricultural Society was created June 9, 1849 and they held their first fair on Sept. 28 and 29, 1849. About 2000 people attended the fair. Expenditures was $176 in premiums and $4 for the services of the secretary. A profit of $40 was made for the society.

The fair was moved to Owensville in 1864 where it has been held ever since. The site originally had 24 acres which had been purchased for $45 an acre. The Floral Hall is on the same site as it was in 1864.

It is believed that the first baby contest was held in 1878. The top prize was $5. The first known bicycle races took place in 1895 with a purse of $50.

In 1910, another 25 acres was purchased to enlarge the size of the fairgrounds and in 1911, the first grandstand was built.

Over the years, many additional buildings have been built, the midway's gravel has been replaced with blacktop, electricity has been added and upgraded continuously, and the grandstand rebuilt after it was destroyed in a fire in 1969. The fair has grown from a 2 day to a 7 day event and attendance has reached the 80,000 mark.