The island of Guernsey was formed about 6000 years B.C. when as a result of thawing of glaciers of water of English Channel at first turned it into the peninsula, and then completely separated it from continental Europe.  At that time this island was occupied by peasants who left after itself menhirs and the dolmens which have remained and to this day. 

Set of excavation in the capital of the island of Sent-Peter-Port testify that from 56th year of our era Romans used the island of Guernsey as a trade point between France and England and remained on the island up to 250. The Christianity on the island of Guernsey was established in the III-IV centuries by the priest from Brittany, Saint Sampson.

In 933 the island of Guernsey, as well as all Channel Islands, became part of the Norman Crown. In 1066 the Duke Norman carried out the last successful gain of the British island and became king William the Conqueror. However when king John lost the territory of Normandy, having conceded it to the king of France Philippe II, Norman islands kept the citizenship to the English crown. In exchange on citizenship in 1215 king John granted to islands a number of the rights and privileges, including the right to self-government and tax exemption.

In the Middle Ages the island of Guernsey repeatedly was attacked by the French pirates and naval forces, especially during Centenary war when the island was repeatedly occupied by the French army. During the next centuries the island of Guernsey six times serially took over England and France. In an interval between 1340 and the beginning of the XV century the island was occupied by France. In 1480 Pope Sikst of IV proclaimed the island of Guernsey the neutral state and in 1481 Gernsiysky states were created.

At the beginning of the XIX century owing to Napoleonic wars trade activity on the island was almost nullified. It resulted in unemployment, weakening of sea protection and to economy decline. In 1816 after numerous debate Consultative states made for the first time the decision on release of own banknotes. In 1926 the island of Guernsey officially accepted English, and the currency of the island was attached to English pound sterling.

During World War II in 1940-1945 of the island of Guernsey were occupied by the German armies which constructed a huge number of the defensive works being part of the Atlantic wall of Hitler. Before war about 17 000 people from 40 000 population of islands were evacuated to England for the period of war. During occupation many people were deported in German camp in the southeast of Germany. Islands were freed 1945. And every year inhabitants of islands celebrate the release on May 9. In post-war time of the island of Guernsey became a popular place for tourism. In 1973 of the island of Guernsey became the member of the European Trade Community.