It is located in Colombo Fort in close proximity to the President's House, and it was known as the Senate Building until 1972.

From then until Ceylon's Independence in 1948, the Republic Building housed several government departments.

Following independence, the building hosted the Senate of Ceylon, the Prime Minister's Office, the Cabinet office and the Ministry of External Affairs and Defence.

The Republic Building is situated along what was once Queen's Street facing the Gordon Gardens across the road.

The section of the road between the Church Street juncture and the Sir Baron Jayathilaka Mawatha Street juncture has been closed off and has since been known as Republic Square.