Most people pass through its gates for a civic function or a public event without pausing to consider that the building beneath the Victorian stucco and the elaborate ironwork is considerably older than it looks.

The Mansion House was built in 1710, making it one of the earliest surviving substantial urban residences in the city. It was acquired by Dublin Corporation shortly after its construction to serve as the official residence of the Lord Mayor, a function it has held ever since, giving it the distinction of being the longest continuously used mayoral residence in these islands. The Round Room attached to the main house was added in the nineteenth century and has its own civic weight; it was here that the First Dáil convened in January 1919, assembling for the first time as a self-declared Irish parliament separate from Westminster.

The house sits on Dawson Street in the south city, easily reached on foot from St Stephen's Green. The building is not generally open to the public as a museum, since it remains a working official residence, but the exterior repays attention. The forecourt gates and the decorative facade give little indication of the 1710 core behind them, and that layering of periods is itself worth noticing. Occasional open days and civic events provide access to the interior, including the Oak Room, which contains period panelling and portraits accumulated over three centuries of mayoral occupation. Checking Dublin City Council's public calendar before a visit is the most reliable way to find a legitimate opportunity to go inside.