Mountjoy Square, Georgian garden square in Dublin, Ireland

Mountjoy Square is a Georgian garden square in Dublin, Ireland, surrounded by red-brick terraced houses. The square is a perfect square with each side measuring 140 metres, and the houses are numbered continuously clockwise from the northwest corner.

Mountjoy Square was developed in the late 18th century by Luke Gardiner, 1st Viscount Mountjoy, with construction starting in 1792 and finishing in 1818. In 1938, the park passed from private to public ownership.

The square has been home to many writers and artists, and today the park is a gathering place for locals. The granite sundial in the park dates back to the 1800s, and there are mosaic tree surrounds depicting traveller life.

The park in the centre is open daily, with longer hours in summer, and has a playground, tennis courts, and a football pitch. It is wheelchair accessible, and the surrounding streets are flat and easy to walk.

Mountjoy Square is Dublin's only true Georgian square, with each side exactly 140 metres long. The square was originally planned to have a church in the centre, but this was never built.