March 10 – The first census is held in Great Britain. The population of England and Wales is determined to be 8.9 million, with London revealed to have 860,035 residents. 1.5 million people live in cities of 20,000 or more in England and Wales, accounting for 17% of the total English population.
24 December – Cornish engineers Richard Trevithick and Andrew Vivian demonstrated Puffing Devil, their steam-powered road locomotive, in Camborne. The trial was successful but Trevithick realised the limitations of steam power in a road-running vehicle and turned his attention to rail, introducing the world's first steam railway locomotive in 1804.
Philippe Pinel publishes Traité médico-philosophique sur l'aliénation mentale; ou la manie, presenting his enlightened humane psychological approach to the management of psychiatric hospitals. Translated into English by D. D. Davis as Treatise on Insanity in 1806, it is influential on both sides of the Atlantic during the nineteenth century.