Hi Elelyn,
The National University in Galway has a record of the main estates in Co. Galway and other Counties. Try Landed Estate NUI. Not responding at the moment!
Attached is a record of a "Harry Dempsey" in 1845. He was acting as a Guarantor for Sibby Madden who as obtaing a small loan. He may be of interest to you?
Credits: www.findmypast.ie
Regards,