Castletown's civic identity is older than its civic premises. The first thing locals called a 'town hall' was a private venture - a group of businessmen who formed a company in the 1850s and built a neoclassical assembly hall on Arbory Street, foundation stone laid in March 1856 by James Gell, the High Bailiff. It had a six-column Doric portico and a main hall 68 metres long. The Manx poet Thomas Edward Brown gave his last performance there in 1897. The Order of Odd Fellows took it over later, and in 2004 it became the Castletown Youth Centre. It served the town for nearly 150 years, but it was never municipal. Real town business happened wherever the commissioners could find a desk.

After being appointed in 1883, the new town commissioners moved into a building on the south side of Market Square - originally a pub called The George, owned in the late 1700s by John Murray, the 4th Duke of Atholl. The War Office bought it in 1828 and turned it into barracks. The town commissioners bought it from the War Office in 1911, fitting their offices into a five-bay symmetrical frontage with cement render and casement windows. After the commissioners moved out, the building was renamed Manannan House and became a coffee shop with a gym above. In 1973, the National Westminster Bank gave the commissioners the Old House of Keys - the former meeting place of the Manx parliament before it moved to Douglas in 1874 - on the condition that it serve the town. The commissioners ran their business from there for sixteen years.

By the mid-1980s, the Old House of Keys was no longer adequate. The commissioners selected a site on the north side of Farrants Way and commissioned a modern complex from a local contractor, Kelly & Bridson. The design was deliberately functional - three blocks of brick with a cement-render finish, no Doric porticos, no neoclassical pediments. A two-storey town hall on the left, a single-storey entrance block in the centre with a small stone porch, and a two-storey library to the right. It opened on 16 March 1989. It is the kind of building that doesn't aim to charm - and on a town square half a mile away that still contains medieval Castle Rushen and the Georgian Old House of Keys, that probably was the point. Civic Castletown finally had a building that admitted to being a building.

The library extension came first - an additional wing completed in November 1999, recognising that a small Manx town's public library still functioned, as public libraries everywhere do, as the closest thing many residents had to a community room. Then in November 2017 the police service moved in, taking over part of the space the library had vacated during the expansion. The arrangement - library, police, commissioners under one roof - has the slightly improvised quality of small-town municipal life everywhere: institutions that share buildings because the town is too small to justify separate ones, and because no one in Castletown is more than a few minutes' walk from anyone else anyway. The Old House of Keys, freed of its administrative duty in 1989, was renovated as a museum by Manx National Heritage and reopened to visitors in 2000.

Castletown is full of louder, older buildings. The medieval castle dominates the harbour. The narrow lanes hold limestone Georgian houses, cottages where George Quayle hid his eighteenth-century inventions and possible smuggling operation, the disused Arts and Crafts police station designed by Baillie Scott opposite the castle entrance. The Civic Centre on Farrants Way does not compete. It is brick, it is functional, and it does the work that a town hall is supposed to do - issue planning notices, host commissioners' meetings, run the library where children sit on the carpet at story time. After a century of borrowed rooms and converted barracks, that's perhaps the most useful thing a Castletown civic building could possibly be.