In Gallo-Roman times, Guernsey, Sark and Herm formed one large island. Another island was situated south of Jersey, now forming the rocky area of Les Minquiers. Jersey, Alderney, Les Ecréhous and Chausey were part of the continent at this time. A Roman way used to join Alderney to La Hague, an other one lead from Jersey to Portbail. A large forest named Forêt de Scissy grew around Chausey and the bay of Mont Saint Michel. Old tales of Normandy tell that during an night in March 709, a huge tidal wave devastated western Norman and northern Brittany coasts. The forest was destroyed, Mont Saint Michel isolated and villages and pastures drowned under sea. Jersey, Alderney, Chausey and Les Ecréhous became islands. Guernsey, Herm and Sark were separated. During the following centuries and to this day, the sea has been carrying on this work and continues to slowly erode the littoral.

People have lived in these countries since 250,000 BC, and the islands were invaded by Romans at the beginning of our era. They were then converted to Christianity by Saint Helier in the 6th century, "visited" by Vikings, then annexed by Normans in 933. In 1066, William the Conqueror (Guillaume le Conquérant), Duke of Normandy, became King of England. The islands then became Anglo-Norman. The first castle on the islands, Le Château du Roi, later renamed Castle Cornet, was built in Guernsey in 1204, when King John (Jean-Sans-Terre) lost the Duchy of Normandy to Philipp August (the King of France). Islanders remained faithful to their Duke... the King of England. In the 13th & 14th centuries, the islands had to face several French attacks and occupations. In the 18th century, French armies threatened the Islands again and defence towers were erected all around the islands. They were completed with new fortifications on 19th century. In June 1940 the German troops occupied the islands and constructed massive defensive works, turned this time, against Great Britain. The Channel Islands were not liberated until the 9th of May 1945, after the signature of general surrender ended all second world war hostilities.

The Norman dialect grew from Roman spoken during the 11th century and very similar to the language used in the Chanson de Roland and Le Roman de Rou by Jersey writer Robert Wace, remained the natural islands language until the beginning of the 20th century. This is the reason why many places and villages have kept their French names. Commerce with England introduced English language on the islands. During the first world war, many islanders served in the British Army, and became accustomed to English. In 1940, many of the islanders were evacuated and dispersed to various regions of Great Britain, and learned English. The growth of British tourism, radio and television, trade and education seriously reduced the use of Norman patois. As in the Cotentin, only a few people hang on their traditions, sometimes using Norman patois between themselves. Initiatives in both Jersey and Guernsey are actively encouraging the younger generation to learn their native language: Jersey. Guernsey.

The Channel Islands are British Crown Dependancies but are not part of the United Kingdom. Islanders recognize their sovereign only through his title of Duke of Normandy title. Islands States (Governments) promulgate their own laws, some of them dating from medieval times, and customs. Jersey and Guernsey print their own stamps and have their own, sterling based, currency.

Because of their own tax systems, the islands have become some of the most important financial centres in the world. Whilst not members of the European Union, the islands are part of the European Economic Area and attract a large amount of inward investment, companies and multimillionaires. Agriculture and tourism have an important role in the islands economy.

Islanders are entitled to British (Channel Islands) passports allowing free movement and residence within the EU.

The Bailiwick of Jersey includes Les Minquiers and Les Ecréhous. The Bailiwick of Guernsey encompasses Alderney, Sark, Brecqhou and Herm. Alderney and Sark have their own governments although some matters are dealt with by the States of Guernsey.