Here is what the Preble County book put out by the Preble County Historical Society has to say:
Church of the Visitation of the Blessed Virgin Mary.
The first services of Roman Catholics in Eaton were conducted in 1853. The Church then known as a "station" was founded by Father Carney. St. John's Catholic Church in New Paris was founded in 1879. But it was attended by a priest from Middletown,Ohio as early as 1858. The Church there in New Paris was built in 1872. The first Mass was held in James Horigan residence.
And yes, both of these Churches are in the Cincinnati Diocese.