The year 1790 in architecture involved some significant architectural events and new buildings.

Events

• date unknown – Work begins on the East India Company's Plantation House in Saint Helena, which remains the official residence of the Governor.

Buildings and structures

Buildings completed

• New church of the Abbey of St Genevieve in Paris, designed by Jacques-Germain Soufflot and finished by Jean-Baptiste Rondelet, is completed to serve as the Panthéon.
• Estrela Basilica in Lisbon.
• All Saints church, Wellington, Shropshire, England, designed by George Steuart.
• Royal Observatory in Madrid, designed by Juan de Villanueva.
• Härnösand Residence in Sweden.
• The Pitot House, New Orleans built by Don Santiago Lorreins (bought by James Pitot in 1809).
• The John Dodd Hat Shop in Danbury, Connecticut, built by lawyer John Dodd.
• The bridge at Warwick Castle, England.
• Monmouth County Gaol, UK, designed by William Blackburn.^[1]

Births

• May 4 – Archibald Simpson, Scottish architect practicing in Aberdeen (died 1847)
• November 7 – Karol Podczaszyński, Polish neoclassical architect (died 1860)

Deaths

• February 16 – John Hawks, American architect (born c.1731)^[2]
• November 11 – Nicolò Pacassi, Austrian architect (born 1716)