In the early 20th century, Shire Hall in Dorchester was the local facility for dispensing justice and the meeting place of Dorset County Council.

[5] The foundation stone for the new building at Colliton Park was laid by the Lord Lieutenant of Dorset, the Earl of Shaftesbury, on 26 September 1938.

[6] The design involved a symmetrical main frontage with seventeen bays facing south; the central section of five bays, which projected slightly forward, featured a doorway on the ground floor flanked by two columns with the county coat of arms above; there was a triple window on the first floor and a flagpole at roof level.

[6] A memorial to the soldiers of the 2nd Battalion, the Dorset Regiment who died during the Battle of Kohima, which took place in India in spring 1944 during the Second World War, was unveiled outside County Hall in May 2015.

[12] Works of art in County Hall include a painting by Elizabeth Thompson depicting the 1st Battalion, the Queen's Own Dorset Yeomanry securing a British victory against German and Ottoman-instigated Senussi forces at the action of Agagia which took place in Egypt on 26 February 1916 during the First World War.