Thank you for the reply. While I haven't traced the Carolans on my tree to Mayo, Ancestry.com does have a members connect area that makes suggestions for possible family tree matches, and one family on there is from Mayo.
It looks like their family is John Carolan and Mary Reilly, and from what I can see, they had a son John Carolan (b. 1837) married to Mary Walsh, and they lived in Crossmolina, Co, Mayo. It may help to check this family out. I don't think they are connected to mine, but it's worth sharing the info if it can help you. Who knows, maybe the townland can help you narrow down your search?
There also a ton of other Carolan families in Westmeath, Louth and outside of Belfast. I believe these are connected to my own family.
The Carolans related to my own family were born in Moynalty, Meath, and ended up in Worcester, Massachusetts, Providence, Rhode Island, and Newark, NJ.