Merrion Square (Irish: Cearnóg Mhuirfean) is a Georgian garden square on the southside of Dublin city centre.
The square was laid out after 1762 and was largely complete by the beginning of the 19th century. The demand for such Georgian townhouse residences south of the River Liffey had been fuelled by the decision of the then Earl of Kildare (later the Duke of Leinster) to build his Dublin home on the then undeveloped southside. He constructed the largest aristocratic residence in Dublin, Leinster House, second only to Dublin Castle. As a result of this construction, three new residential squares appeared on the Southside, Merrion Square (facing the garden front of Leinster House), St Stephen's Green and the smallest and last of Dublin's five Georgian squares to be built, Fitzwilliam Square.
Aristocrats, bishops and the wealthy sold their northside townhouses and migrated to the new southside developments.
Merrion Square is considered one of the city's finest surviving squares. Three sides are lined with Georgian redbrick townhouses; the West side abuts the grounds of Leinster House (seat of the Oireachtas), Government Buildings, the Natural History Museum and the National Gallery. The central railed-off garden is now a public park.