Mountjoy Square (Irish: Cearnóg Mhuinseo) is a Georgian garden square in Dublin, Ireland, on the north side of the city just under a kilometre from the River Liffey. One of five Georgian squares in Dublin, it was planned and developed in the late 18th century by the Luke Gardiner, 1st Viscount Mountjoy. It was surrounded on all sides by terraced, red-brick Georgian houses. Construction began in the early 1790s and the work was completed in 1818.Over the centuries, the square has been home to many of Dublin's most prominent people: lawyers, churchmen, politicians, writers and visual artists. The writer James Joyce lived around the square during some of his formative years, playwright Séan O'Casey wrote and set some of his most famous plays on the square while living there, W.B. Yeats stayed there with his friend John O'Leary, and more recently, much of the Oscar-winning film Once was made in the square. Historic meetings have taken place there, including planning for the Easter Rising and some of the earliest Dáil meetings. Prominent Irish Unionists and Republicans have shared the square.Mountjoy can boast being Dublin's only true Georgian square, each of its sides being exactly 140 metres in length. While the North, East and West sides each have 18 houses, the South has 19, reflecting some variation in plot sizes. Though each side was originally numbered individually, the houses are now numbered continuously clockwise from no. 1 in the north-west corner. While its North and South sides are continuous from corner to corner, the East and West sides are in three terraces, interrupted by two side streets, Grenville Street and Gardiner Place to the West and Fitzgibbon and North Great Charles Street to the East. Gardiner Street passes through the West side of the square, while Belvidere Place and Gardiner Lane run off the North- and South-East corners.Although some of the original buildings fell to ruin over the 20th century and were eventually demolished, the new infill buildings were fronted with reproduction façades, so each side of the square maintains its appearance as a consistent Georgian terrace.