The Slane Festival is a recurring concert held most years since 1981 on the grounds of Slane Castle on the outskirts of Slane in County Meath, Ireland. The castle is owned by The 8th Marquess Conyngham, who was known by the courtesy title the Earl of Mount Charles from 1974 until 2009. Slane lies between Navan and Drogheda, about 45 km northwest of Dublin. Concerts typically occur on a Saturday in August, from 12:00 to 22:00. The sloping grounds of Slane Castle form a natural amphitheatre which is ideal for concerts. As many as 70,000–110,000 people usually attend. One of the venue boundaries is the River Boyne. Two people died while trying to swim the river to gain free access to R.E.M.'s concert in 1995. The minimum age of admission to the Slane Festival was reduced in 2006 from 18 to 16 because of complaints.

Slane Castle is located in the village of Slane, within the Boyne Valley of County Meath, Ireland. The castle has been the family seat of the Conyngham family since it was built in the late 18th century, on land first purchased in 1703 by Brig.-Gen. Henry Conyngham.