The year 1808 in architecture involved some significant events.
- Arc de Triomphe du Carrousel, Paris, France.
- Fort Edgecomb, an octagonal, wooden, two-story blockhouse, built in Lincoln County, Maine, USA, to protect Wiscasset's seaport (settled in 1663 on the tidal waters of the Sheepscot River).
- Fountain in front of Mission Santa Barbara, California, USA.
- Hotel Polski, Warsaw, Poland.
- Potseluev Bridge (new cast-iron bridge) across the Moyka River in Saint Petersburg, Russia.
- Sheffield Old Town Hall, England, UK.
- Leeds Library, England, UK, by Thomas Johnson.
- Sparks Shot Tower in Philadelphia, Pennsylvania, USA.
- Teatro della Concordia, designed by Luigi Canonica, in Cremona, Italy.
- Reconstruction of palace at Natolin, Poland, by Chrystian Piotr Aigner for Stanisław Kostka Potocki.