Newgrange, Ireland

There is most likely public bus service to a nearby town, but it would then require a taxi from there to the actual visitor center. You might want to look into taking a tour there instead. For one thing, the tours have a guarantee of getting to go inside the vault. If you're going in a busy tourist season, if you go too late in the day they may have already booked their spots for the day (you pay at the visitor center, then take a shuttle bus to the actual site).

I believe it is the Dublin to Belfast bus that stops in Drogheda and then there are several buses a day that go from Drogheda to the parking lot at Newgrange. www.buseireann.com. As Nancy said if you just show up at the visitors center and are not part of a tour group you are not guaranteed entrance inside the structure. I do not think this is a problem in the off season but can be during the summer months. The Bus Eireann tour is good and the Mary Gibbons tour is highly recommended.

When you arrive in Dublin, look for the TI adjacent to Dublin Castle, in a converted church. They can give you information on bus tours to Newgrange.

We took a bus Eirenn tour (Boyne Valley tour) out of the main bus station. We went the day before to buy our tickets and showed up the next morning for the trip. The bus stopped at Newgrange and Hill of Tara long enough to tour each area. It may stop at Trim Castle now, it was under construction when we were there. It also stops briefly at the location of the Battle of the Boyne.

The trip was a great value.

They also have a trip to Glendalough, the other direction from Dublin, that I would have liked to have taken if I had another day.

I just came back from Ireland two days ago, and I took a Mary Gibbons tour to Newgrange and the Hill of Tara - I highly recommend touring with her. She is extremely knowledgeable, and I learned a lot about both sites along with Irish history to the present day.