The year 1843 in architecture involved some significant events.

Buildings and structures

Buildings

• March 25 – The Thames Tunnel in London, constructed by Isambard Kingdom Brunel and Marc Isambard Brunel,^[1] the oldest underwater tunnel in the world, opens to the public.^[2]
• Nelson's Column in London, designed by William Railton, is completed.
• McGill University's original building, later known as the Arts Building, is completed in Montreal by architect John Ostell.

Awards

• Grand Prix de Rome, architecture: Jacques-Martin Tétaz.

Births

• July 6 – Robert S. Roeschlaub, German-born architect working in Colorado (died 1923)
• November 29 – Gertrude Jekyll, English garden designer (died 1932)

Deaths

• January 13 – Peter Atkinson, English-born architect (born 1776)