Although they are not part of the United Kingdom,[3] the UK is responsible for the defence and international relations of the islands as it is for the other Crown Dependency, the Isle of Man, and the British Overseas Territories.

Each has its own independent laws, elections, and representative bodies (although in modern times, politicians from the islands' legislatures are in regular contact).

The earliest evidence of human occupation of the Channel Islands has been dated to 250,000 years ago when they were attached to the landmass of continental Europe.

The numerous dolmens and other archaeological sites extant and recorded in history demonstrate the existence of a population large enough and organised enough to undertake constructions of considerable size and sophistication, such as the burial mound at La Hougue Bie[9] in Jersey or the statue menhirs of Guernsey.

Hoards of Armorican coins have been excavated, providing evidence of trade and contact in the Iron Age period.

[10]: 4  The traditional Latin names used for the islands (Caesarea for Jersey, Sarnia for Guernsey, Riduna for Alderney) derive (possibly mistakenly) from the Antonine Itinerary.

But there were not enough of them to leave any trace, and the islands continued to be ruled by the king of the Franks and its church remained part of the diocese of Coutances.

In 933, the islands were granted to William I Longsword by Raoul, the King of Western Francia,[12] and annexed to the Duchy of Normandy.

Edward III of England granted a Charter in July 1341 to Jersey, Guernsey, Sark and Alderney, confirming their customs and laws to secure allegiance to the English Crown.

[13]: 2–4  Owain Lawgoch, a mercenary leader of a Free Company in the service of the French Crown, attacked Jersey and Guernsey in 1372, and in 1373 Bertrand du Guesclin besieged Mont Orgueil.

[13]: 5–10  Jersey was occupied by the French in 1461 as part of an exchange for helping the Lancastrians fight against the Yorkists during The War of the Roses.

This privilege of neutrality enabled islanders to trade with both France and England and was respected until 1689 when it was abolished by Order in Council following the Glorious Revolution in Great Britain.

Control by the bishop of Winchester was ineffectual as the islands had turned overwhelmingly Calvinist and the episcopacy was not restored until 1620 in Jersey and 1663 in Guernsey.

[19][20] Sir Edmund Andros, bailiff of Guernsey, was an early colonial governor in North America, and head of the short-lived Dominion of New England.

In Alderney, the occupying Germans built four prison camps which housed approximately 6,000 people, of whom over 700 died.

There was considerable hunger and privation during the five years of German occupation, particularly in the final months when the population was close to starvation.

Many Spaniards, initially refugees from the Spanish Civil War, were brought to the islands to build fortifications.

The legislatures were reformed and non-party governments embarked on social programmes, aided by the incomes from offshore finance, which grew rapidly from the 1960s.

Although the words derive from a common root ('bail' = 'to give charge of') there is a vast difference between the meanings of the word 'bailiff' in Great Britain and in the Channel Islands; a bailiff in Britain is a court-appointed private debt-collector authorised to collect judgment debts, in the Channel Islands, the Bailiff in each bailiwick is the civil head, presiding officer of the States, and also head of the judiciary, and thus the most important citizen in the bailiwick.

In the early 21st century, the existence of governmental offices such as the bailiffs' with multiple roles straddling the different branches of government came under increased scrutiny for their apparent contravention of the doctrine of separation of powers—most notably in the Guernsey case of McGonnell -v- United Kingdom (2000) 30 EHRR 289.

That case, following final judgement at the European Court of Human Rights, became part of the impetus for much recent constitutional change, particularly the Constitutional Reform Act 2005 (2005 c.4) in the UK, including the separation of the roles of the Lord Chancellor, the abolition of the House of Lords' judicial role, and its replacement by the UK Supreme Court.

[47] Normandy Trader operates an ex military tank landing craft for transporting freight between the islands and France.

[49] Senator Alan Maclean, a Jersey politician, had previously tried to save the 90-odd jobs furnished by the company to no avail.

[53] The Norman language predominated in the islands until the nineteenth century, when increasing influence from English-speaking settlers and easier transport links led to Anglicisation.

[55] Victor Hugo spent many years in exile, first in Jersey and then in Guernsey, where he finished Les Misérables.

[57] The annual "Muratti", the inter-island football match, is considered the sporting event of the year, although, due to broadcast coverage, it no longer attracts the crowds of spectators, travelling between the islands, that it did during the twentieth century.

In 2001 and 2002, the Channel Islands entered a team into the MCCA Knockout Trophy, the one-day tournament of the minor counties of English and Welsh cricket.

At the Reformation, the previously Catholic islands converted to Calvinism under the influence of an influx of French-language pamphlets published in Geneva.

Anglicanism was imposed in the seventeenth century, but the Nonconformist local tendency returned with a strong adoption of Methodism.

In the late twentieth century, a strong Catholic presence re-emerged with the arrival of numerous Portuguese workers (both from mainland Portugal and the island of Madeira).