In 1889 the Blenheim Borough Council decided to grant a request of Mr Fred Hale, Secretary of the Garrison Band, to erect a band rotunda in Market Place in central Blenheim. The site where the Rotunda now stands was initially occupied by a well. This was later filled in and replaced with a magnificent cast iron fire hydrant with five outlets. The hydrant was removed, and in December 1889, the concrete base of the Rotunda was poured on the site. However the Council was unhappy with the cost of the project and development was halted for three and a half years.

When the decision was made to complete the Rotunda a committee, headed by Mr G.W. McIntosh, was established to design it. The Rotunda is an excellent example of the ornate design and workmanship that characterised the turn of the century. The four-sided structure has impressive ornamental ironwork around the roof and between the tops of the eight iron poles that support it. There are also beautiful ironwork panels in each corner, which feature floral designs.

Paid for by public subscription, the Rotunda was finally completed in July 1903. A bronze dedication plaque noting the occasion was later attached to one of the panels. The building was named the Cleghorn Memorial to commemorate Blenheim's famous medical practitioner, George Cleghorn (1850-1902), who had died the previous year. Dr. Cleghorn was born in India and studied medicine at St Thomas's Hospital, London. He came to Blenheim in 1876 and entered into a partnership with Dr. L. K. Horns. Dr Cleghorn built up a reputation throughout New Zealand as a fine abdominal surgeon. His skill as a surgeon was demonstrated when he operated for appendicitis on Caleb Higgs in Renwicktown, in what is believed to be the earliest successful appendectomy in New Zealand. He was also one of the first to realise the value of antiseptics. Dr. Cleghorn endeared himself to the people of Blenheim for his understanding and kindness, and for his readiness to treat patients he knew did not have the money to pay him.

Since the Rotunda was built it has been used for more important occasions than any other place in Blenheim. On its platform have stood governor generals, mayors, royalty, lords and ladies, statesmen, generals, sportspeople and other notables. Every important occasion has seen crowds gather in Market Place. From the Rotunda, service men and women have been farewelled and welcomed home, and declarations of peace have been celebrated. In 1953, a proposal by a small group of citizens to remove the Rotunda led to an emotive debate against the proposal through letters to the editor in the Marlborough Express, demonstrating the strong cultural, social and historic values that Blenheim residents attribute to the Cleghorn Rotunda.

For its centennial in 2003, the Marlborough District Council carried out extensive restoration work on the Rotunda. This included the replacement of some ornamental ironwork and the addition of three mock gas lamps to adorn the top of the Rotunda. The Council used old photos of the Rotunda to make sure the restoration work was true to the original design of the Rotunda. A second plaque was installed on the Rotunda at the time of the restoration.

The Cleghorn Rotunda in Blenheim's Market Place was completed in memory of the late Dr. Cleghorn, to commemorate all he had done for Blenheim and people throughout New Zealand. The Rotunda has architectural value as an example of the design styles characteristic of turn of the century, and social value as a focal point in Blenheim.