The initial project for this building made of Galician ashlar was led by Pedro Mariño. It has a floor area of 2,300 square metres consisting of 3 storeys and an attic. Its façade was built along a front measuring 64 metres. It has 43 windows open to the exterior, and its interior has 15 arcades that rest on wide pillars.

On the first floor is the bel étage, which has several lounges - the Red, the Blue and the Golden, the latter with reliefs on the front of the seats which relate the most important historical events of the city. Also on the first floor is the Clock Museum  and the Gallery of the Mayors, a corridor where each of the mayors of the city has a portrait, each one by a different artist and with a different style, with many posed wearing suits, some in tails and others, like Liaño Flores, in his lawyer's robes.

Worth a visit are the Mayor's Office and, on the same floor, the Council Chamber, with magnificent paintings by Galician artists. It is also worth mentioning the staircase of honour that connects the Mayor's Office with the Legislative Chamber, which was inaugurated in 1955 by dictator Francisco Franco and his wife, Carmen Polo.

The first floor houses offices, and the attic is where the caretaker's quarters used to be located.

On the façade, there are four carved white stone statues representing the four Galician provinces of A Coruña, Lugo, Ourense and Pontevedra. At the top, the city's coat of arms can be seen flanked by two matrons, which for some signify Peace and Industry and for others Work and Wisdom, as well as a legend with the following inscription: "very noble and very loyal city of La Coruña, head, guard and key, strength and antemural of the Kingdom of Galicia".

The highest tower houses the clock, with its bells made of an alloy of bronze and tin; they weigh more than 1,600 kilos.