It’s hard to find trustworthy, well-researched information about Irish names of people or places. Baby name books are notoriously full of lies and half-truths, and there’s lots of well-intentioned blarney everywhere. However, you don’t have to break out the Old Irish dictionary yourself. There is now a very nice online database to help you!
If you want to know about the meaning of placenames, such as the townland where your family came from, logainm.ie will do it.
(The name is short for Bunachar Logainmneacha na hEireann, Placenames Database of Ireland. Ainm is “name,” and logainm is “placename.”)
The site is available in English and Irish; and there’s a feature that lets you listen to the local pronunciation so you won’t sound like an idiot. It’s sponsored by Dublin University.
If you only have the name of a townland, street, or place, and you don’t know where it is, the database will also tell you the county and barony it’s in (or was in). So people might find it very useful.