Searching for Patrick Keating (b circa 1820)

I am searching for information on Patrick (b circa 1820) and Ellen (b circa 1821) in County Galway.  They emmigrated to Baltimore, Maryland, USA around 1850 with two daughters, Bridget and Jane..  We believe Ellen's maiden name was McNeal.  The following obituary from 1879 is the only information we have on his origins:

"DIED

CATON. – On September 21 (187), after a lingering illness, PATRICK CATON, in the 56th year of his age, a native of the parish of Kilkrone, county Galway, Ireland.  May he rest in peace, Amen.  [Indiana and New York papers please copy.]

                His friends are respectfully invited to attend his funeral, from his late residence, Gould lane, between Brown and West streets, on tomorrow (Tuesday) afternoon, at two o’clock."

I searched online for parishes that sound like "Kilkrone" and Kilcroan seemed similiar, but there seem to be others with similiar names.

Does anyone have any suggestions on how I can seach for these people?