1900
- 1904 - Cornwall accepted into Celtic Congress
- 1906 - Bodmin by-election, 1906
- 1910 - Truro Cathedral completed.
- 1920 - First Old Cornwall Society founded in St Ives.
- 1921 - Cornwall's deepest mine, the 3,500 ft Dolcoath mine, closes.
- 1922 - Bodmin by-election
- 1928 - First Gorseth Kernow at Boscawen-un, (instituted by Henry Jenner) symbolising the resurgent interest in Cornwall's Celtic cultural and linguistic heritage. Cornwall College founded; St Ives by-election, 1928
- 1930s - Unified Cornish developed.
- 1932 - North Cornwall by-election, 1932
- 1935 - Silas Kitto Hocking is the first author to sell a million books in his lifetime.
- 1937 -St Ives by-election, 1937
- 1939 - North Cornwall by-election, 1939
- 1944 - Hill 112 in Normandy acquired the name "Cornwall Hill" after Cornish soldiers of 5th Duke of Cornwall's Light Infantry suffered 320 casualties in the fighting here.
- 1951 - Cornish political party, Mebyon Kernow, or ("Sons of Cornwall"), was formed.
- 1953 - Mebyon Kernow wins first council seat.
- 1954 - The first of three Formula 1 motor races was held at the Davidstow Circuit
- 1961 - Celtic League founded at Rhos near Wrexham, includes Cornish branch.
- 1962 - Goonhilly Receiving Station started, receives first transatlantic TV broadcast.
- 1964 - Commercial helicopter service to Isles of Scilly is first in Europe.
- 1966 - Closure of the railway line between Halwill Junction and Wadebridge
- 1967 - Closure of the railway line between Wadebridge and Padstow
- 1967 - The Torrey Canyon supertanker disaster causing severe damage to the nearby sea and coastline.
- 1971 - The Kilbrandon Report into the British constitution recommends that use of the term Duchy to refer to Cornwall as a whole "on appropriate occasions" would recognise the "special and enduring relationship between Cornwall and the Crown".
- 1972 - Local Government Act 1972: special dispensation for Scilly.
- 1973 - The UK joins the EEC, which was to become the EU.
- 1979 - First European Parliament election contested in Cornwall and Plymouth (European Parliament constituency)
- 1980s - Split in Cornish language revival, with Modern Cornish and Kernewek Kemmyn being developed.
- 1983 - 1983 British Airways Sikorsky S-61 crash
- 1987 - Cornwall has Britain's first air ambulance service.; Truro by-election, 1987
- 1988 - water pollution incident at Camelford. 20 tonnes of aluminium sulphate were accidentally emptied into reservoir, tainting the water supply to 20,000 people, causing brain damage in some cases.
- 1991 - First windfarm in Cornwall.
- 1992 - Pirate FM launched. First commercial station in Cornwall.
- 1993 - Tate St Ives art gallery in St Ives, opened.
- 1993 - The joint Cornwall and Devon bid for Objective One funds fails because of Devon's high GDP.
- 1997 - Keskerdh Kernow 500 march to London.
- 1998 - South Crofty tin mine closes in March 1998 when ores began to be produced more cheaply abroad.
- 1999 - English China Clays taken over by French owned company, Imerys in a £756m deal.
- 1999 - South West Regional Assembly established, but is not elected.
Read more about this topic: Timeline Of Cornish History