Hello Gail, I am looking at old queries on the site, at the remove you are looking at it is almost impossible to find records but I see that in 1641, this is pre plantion, there is a Robert Ewing holding land in Donegal adn continues to hold it after the plantation of Ulster in 1670, the Down Survey is here, (Down survey means hey laid chains on the ground to measure the land, the laid it down, for years I thoought it referred to County Down, you can see the various land owners here https://downsurvey.tchpc.tcd.ie/index.html ;
There is also a subscription site here but you can look up surname locations here, it defaults to Griffiths Valuation on a search, that is 1848 to 1864 to cover the entire country, shows the location of all Ewing's in any particular survey that was done. https://www.johngrenham.com/surnames/
There may be wills etc to see if they left what to who but you are in the realm of a professional genealogist assistance at that point, land registration only commenced in the early 1700s but was not mandatory until much later.
Good Luck
Pat
