In 1498 French Guiana was first visited by Europeans when Christopher Columbus sailed to the region on his third voyage and named it the "Land of pariahs". In 1604 France attempted to settle in the area, but was forced to abandon it in the face of hostility from the Portuguese, who viewed it as a violation of the Treaty of Tordesillas. French settlers returned, however, in 1643 and managed to establish a settlement at Cayenne along with some small-scale plantations. This second attempt would again be abandoned following Amerindian attacks. The French returned once more in 1664, and founded a second settlement at Sinnamary (this was attacked by the Dutch in 1665).
After the Treaty of Paris in 1763, which deprived France of almost all her possessions in the Americas other than Guiana and a few islands, Louis XV sent thousands of settlers to Guiana who were lured there with stories of plentiful gold and easy fortunes to be made. Instead they found a land filled with hostile natives and tropical diseases. One and a half years later only a few hundred survived. These fled to three small islands which could be seen off shore and named them the Iles de Salut (or "Islands of Salvation"). The largest was called Royal Island, another St. Joseph (after the patron saint of the expedition), and the smallest of the islands, surrounded by strong currents, Île du Diable (the infamous "Devil's Island"). When the survivors of this ill-fated expedition returned home, the terrible stories they told of the colony left a lasting impression in France.
In 1794, after the death of Robespierre, 193 of his followers were sent to French Guiana. In 1797 the republican general Pichegru and many deputies and journalists were also sent to the colony. When they arrived they found that only 54 of the 193 deportées sent out three years earlier were left; 11 had escaped, and the rest had died of tropical fevers and other diseases. Pichegru managed to escape to United States and then returned to France where he was eventually executed for plotting against Napoleon.
Later on, slaves were brought out from Africa and plantations were established along the more disease-free rivers. Exports of sugar, hardwood, Cayenne pepper and other spices brought a certain prosperity to the colony for the first time. Cayenne, the capital, was surrounded by plantations, some of which had several thousand slaves.
In 1809 an Anglo-Portuguese naval squadron took French Guiana (ousting governor Victor Hugues) and gave it to the Portuguese in Brazil. However with the signing of the Treaty of Paris in 1814 the region was handed back to the French, though a Portuguese presence remained until 1817.
In 1848 France abolished slavery and the ex-slaves fled into the rainforest setting up communities similar to the ones they had been stolen from in Africa. Now called Maroons, they formed a sort of buffer zone between the Europeans who settled along the coast and main rivers, and the unconquered, and often hostile, Native American tribes of the inland regions. Without the availability of slave labour the plantations were soon taken over by the jungle, and the planters ruined.
In 1850 several shiploads of Indians, Malays and Chinese were brought out to work the plantations but, instead, they set up shops in Cayenne and other settlements.
In 1852 the first shiploads of chained convicts arrived from France. In 1885, to get rid of habitual criminals and to increase the number of colonists, the French Parliament passed a law that anyone, male or female, who had more than three sentences for theft of more than three months each, would be sent to French Guiana as a "relégué." These relégués were to be kept in prison there for six months but then freed to become settlers in the colony. However, this experiment was a dismal failure. The prisoners were unable to make a living off the land and so were forced to revert again to crime, or to eke out a hand-to-mouth existence until they died. In fact, being sent to French Guiana as a relégué was a life sentence, and usually a short life sentence, as most of the relégués died very quickly from disease and malnutrition. The prisoners would arrive at St Laurent du Maroni before being transported to various camps throughout the country. The Iles du Salut were used to house political prisoners and for solitary confinement. The islands became notorious for the brutality of life there, centering around the notorious Devil's Island. Famous political figures to be sent to the islands included Alfred Dreyfus and Henri Charrière, who managed to escape. He later wrote a best-selling book about his experiences called Papillon.
In 1853, gold was discovered in the interior, precipitating border disputes with Brazil and Dutch Guiana (these were later settled in 1891, 1899 and 1915, though a small region of the border with Suriname is still disputed).
After the fall of France to Nazis in World War II the local government declared its allegiance to the Vichy government, despite widespread support for Charles de Gaulle. This government was later removed by the Allies in August 1944.
The infamous penal colonies, including Devil's Island, were gradually phased out and then formally closed in 1951. At first, only those freed prisoners who could raise the fare for their return passage to France were able to go home, so French Guiana was haunted after the official closing of the prisons by numerous freed convicts leading an aimless existence in the colony.
Visitors to the site in December 1954 reported being deeply shocked by the conditions and the constant screams from the cell-block still in use for convicts who had gone insane and which had only tiny ventilation slots at the tops of the walls under the roof. Food was pushed in and bodies removed once a day.
In 1964 Kourou was chosen to be launch site for rockets, largely due to its favourable location near the equator. The Guiana Space Centre was built and became operational in 1968. This has provided limited local employment and the mainly foreign technicians, and hundreds of troops stationed in the region to prevent sabotage, bring income to the local economy.
The 1970s saw the settlement of Hmong refugees from Laos in the county, primarily to the towns of Javouhey and Cacao. The Green Plan (Plan Vert) of 1976 aimed to improve production, though it had only limited success. A movement for increased autonomy from France gained momentum in the 70's and 80's, along with the increasing success of the Parti Socialiste Guyanais.
Protests by those calling for more autonomy from France have become increasingly vocal. Protests in 1996, 1997 and 2000 all ended in violence. While many Guianese wish to see more autonomy, support for complete independence is low due to large economic support from France.