Thomas Hamilton was a Scottish architect, based in Edinburgh where he designed many of that city's prominent buildings. Born in Glasgow, his works include: the Burns Monument in Alloway; the Royal High School on the south side of Calton Hill ; the Royal College of Physicians of Edinburgh; the George IV Bridge, which spans the Cowgate; the Dean Orphan Hospital, now the Dean Gallery; the New North Road Free Church, now the Bedlam Theatre; Cumstoun, a private house in Dumfries and Galloway; and the Scottish Political Martyrs' Monument in Old Calton Cemetery, Edinburgh.

The Old Royal High School, also known as New Parliament House, is a 19th-century neoclassical building on Calton Hill in the city of Edinburgh. The building was constructed for the use of the city's Royal High School, and gained its alternative name as a result of a proposal in the 1970s for it to house a devolved Scottish Assembly.