Hi,
There is a Downing Cemetery,
http://files.usgwarchives.net/ky/mason/. There also is a court record on this same web site with a Downing name.
Anything this old, you'll have to look in the court, land, tax and deed records. The Kentucky Gateway Museum Center,
http://www.kygmc.org/ might have some of those records. They have a Genealogical & historical Research Library with an "extensive collection of books, manuscripts and documents from the past 300 years."
The County Circuit Court Clerk can be found at
http://courts.ky.gov/courts/clerks/Pages/default.aspx?county....
The county was formed in 1788 and earlier records willbe filed in Bourbon County.
The Mason County Clerk's office,
http://masoncountyclerkky.com/ has land records and birth, marriage and death records if there hasn't been a courthouse fire. Successful Searching!