I suspect it might be what is now Clooncon. Clooncon is 77 acres. Have a look to see if the general size of Cloonkilly is about the same as that, and whether some of the names in the tithes are the same in Griffiths Valuation. That may help resolve it.
Many townlands had several names and Griffiths attempted to standardise them, so there are often names in the tithes that have disappeared or changed in the later records.