[6] The building, which was designed by Sir Alfred Brumwell Thomas in the Baroque Revival style, was built in Portland stone at a cost of £369,000 and opened on 1 August 1906.

[11] On 1 August 2006 the City Hall celebrated its centenary with a "Century of Memories" exhibition and family picnic day.

[14] The pediment sculpture is by F. W. Pomeroy, assisted by local carver J. Edgar Winter, and features on the reverse side of the current series of £10, £20, £50 and £100 sterling banknotes issued by the Northern Bank.

[16] Carrara, Pavonazzo and Brescia marbles are used extensively throughout the building as are stained glass windows featuring among others the Belfast coat of arms, portraits of Queen Victoria and William III and shields of the provinces of Ireland.

[19] Visitors can also book free guided tours of the City Hall with access to areas usually closed to the public.

[24] There is also a granite column dedicated to the American Expeditionary Force, many of whom were based in Belfast prior to D-Day, unveiled in 1943.

[25] A 6-foot-high (1.8 m) memorial to Leading Seaman James Magennis VC, made from Portland stone and bronze, was erected in the grounds in October 1999.

[30] On 8 March 2024, bronze statues of the anti-slavery campaigner, Mary Ann McCracken, and the trade unionist, Winifred Carney, were unveiled at a ceremony at Belfast City Hall to coincide with International Women's Day 2024.

[31] Mary Ann McCracken campaigned against slavery at Belfast docks until she was almost 90 years-old[32] and Winifred Carney was a suffragist, committed trade unionist and political activist.