overseas département of France, situated on the northeastern coast of South America. French Guiana has an area of 33,399 square miles (86,504 square km) and is bounded by Brazil to the south and east, Suriname to the west, and the Atlantic Ocean to the northeast. The capital is Cayenne.

Geologically, the rock underlying French Guiana forms part of the crystalline massif of the Guiana Highlands. Rivers, which flow generally northeastward to the sea, have greatly eroded the massif, and most of French Guiana is low-lying. The Maroni River forms the French Guiana–Suriname border in the west, and the Oyapock forms the border with Brazil in the east. The Tumac-Humac Mountains in the south reach an elevation of 2,300 feet (700 metres). Recent alluvial deposits have formed a swampy coastal plain southeast of Cayenne. Older alluvial deposits form a savanna west of Cayenne. Dense tropical forests (mostly hardwood) predominate outside the coastal plain and cover more than four-fifths of the land area. French Guiana is subject to heavy rainfall between December and July; annual rainfall reaches 150 inches (3,800 mm) around Cayenne and tapers off toward the northeast. High temperatures predominate, and monthly averages vary between 77 and 80 °F (25 and 27 °C) at Cayenne. Wildlife includes tapirs, caimans, ocelots, sloths, great anteaters, and armadillos.

French Guiana's population is principally Creole (mixed descent) with minorities of ethnic blacks, American Indians, metropolitan French, Lebanese, Chinese, East Indians, Laotians, Haitians, Brazilians, and Vietnamese. The principal languages spoken are French (official); Creole; Taki-Taki (Sranan), spoken by the ethnic blacks; American Indian dialects; and the various languages of the immigrant communities. The principal religion is Roman Catholicism, adhered to by about 90 percent of the population. Buddhism and Islam are practiced among the East Indians and Southeast Asians. The populace is concentrated principally in and around Cayenne, the largest city, and the coastal regions; the interior is largely uninhabited. Demographic rates are those generally typical of a developing country. There was immigration from Southeast Asia, Haiti, and the French Caribbean territories beginning in the late 20th century.

French Guiana has a developing market economy, patterned on metropolitan France and sustained by aid and technical assistance from France. Services and the production, processing, and export of agricultural, forestry, and fishing products are the largest sectors of the economy. The gross national product (GNP) per capita is one of the highest in South America.

Agriculture produces about one-twentieth of the gross domestic product (GDP) and employs about one-eighth of the registered work force as well as many small subsistence and part-time farmers. Subsistence farming predominates and centres on the growing of cassava, dasheen (taro), sweet potatoes, rice, corn (maize), and bananas and plantains. Most small farms are worked and owned by families, but there are some large estates engaged in growing cash crops, including sugarcane, limes, bananas, and tropical fruits, largely for export to France.

Forests cover more than four-fifths of the land and contain valuable commercial species. Some forestland is reserved by the state, but most is open to exploitation. Most of the timber cut is used for industrial purposes, and of this about two-fifths is exported. Pastures support mainly cattle, pigs, and poultry. Meat and milk production is limited, and large quantities of both must be imported. Shrimps account for most of the annual fish catch.

Mineral industries are of negligible importance, and French Guiana must import mineral fuels and metallic minerals. Gold, gravel, and sand are the only minerals extracted.

The limited manufacturing industries are concentrated on fish, meat, and crop processing and rum and sawn-wood production. Most capital and consumer goods must be imported. Electricity is generated entirely from imported mineral fuels.

Most of the labour force is employed in administration and public services and agriculture. Wages and benefits are legislated at the same rates as those that prevail in France. Unemployment and inflation are high.

Although about two-fifths of the country's roads are paved, the road system is underdeveloped in the interior. Dégrad des Cannes, Larivot, Saint-Laurent du Moroni, and Kourou are principal ports. Some of the country's waterways are navigable by small oceangoing craft, but most are navigable only by shallow-draft vessels. An international airport is at Cayenne. A rocket-launching base at Kourou, used by the European Space Agency, is very important to the economy, accounting for about one-quarter of French Guiana's GDP.

The balance of trade is unfavourable, with exports covering only about one-tenth of imports. Food products, machinery, consumer goods, and refined petroleum dominate imports; shrimps, forest products, and gold are the leading exports. Major trading partners are France and the United States.

French Guiana is governed by the provisions of the French Constitution as an overseas département of France and, as such, forms an integral part of the French Republic. It sends two elected representatives to the National Assembly and one to the Senate. Local government is headed by a prefect and by a 19-member General Council and a 31-member Regional Council; members of both are elected by universal adult suffrage. There is a local court of appeal. The principal political party is the Guianese Socialist Party. Other political parties operate freely and include the Union for a Popular Movement, the Union for French Democracy, the Guiana Democratic Forces, and the Left Radical Party, a part of the Walwari movement.

The social-security system of France is used in French Guiana. It provides payments for work injury, unemployment, and maternity, as well as family allowances and also old-age, disability, and survivor pensions. Health conditions are generally good. The principal causes of death are diseases of the arteries, accidents, and cancer. The Pasteur Institute, located in Cayenne, conducts research on tropical and endemic local diseases and is renowned throughout Latin America. Life expectancy averages 63 years for men and 70 years for women.

Education is free and compulsory between the ages of 6 and 16. Nearly all eligible children attend school. There are private colleges and several teacher-training colleges, and university education is available in France or the French Antilles. The news media are free from direct government control, but subsidies and licensing induce considerable self-control. The principal newspaper is La Presse de Guyane, published in Cayenne.

French Guiana's cultural life reflects the diverse background of the resident ethnic communities. Indigenous and African crafts, customs, and arts predominate among American Indians and ethnic blacks. In the metropolitan areas a distinctive mixed-Creole culture is dominant, highlighted by brilliantly coloured and distinctively patterned costumes; dances reflecting African, East Indian, and French 18th-century influence; and festivals, especially the pre-Lenten Carnival, when much of the population devotes itself to costume design, musical composition, and dance competitions. Léon Damas, a French Guianese poet, was a leader of the Caribbean Modernist literary movement of the 1920s.

Spaniards explored the Guiana coast in 1500 and settled the area around Cayenne in 1503. French merchants from Rouen opened a trading centre in Sinnamary in 1624, followed by others from Rouen or Paris who founded Cayenne in 1643. The Treaty of Breda (Breda, Treaty of) awarded the territory to France in 1667, and the Dutch, who had occupied Cayenne in 1664, were expelled in 1676. Inhabitants of the territory were made French citizens, with representation in the French Parliament after 1877. However, by 1852 the French began using the territory as a penal colony where deported convicts were imprisoned in dreadful conditions exemplified by the notorious Devils Island. More than 70,000 French convicts were deported to French Guiana between 1852 and 1939; the penal colony on Devils Island was abolished only after the startling exposé by Albert Londres (1884–1932). Another aspect of French Guiana, however, was the pioneering community at Mana (1827–46) founded by Anne-Marie Javouhey, mother-superior of the community of St. Joseph of Cluny, who, with Father Francis Libermann, established one of the earliest educational systems for the freed black slaves and women, in the spirit of French Roman Catholic humanism.

French Guiana became a département of France in 1946; it was given regional status in 1974. Its general postwar economic stagnation was partially relieved by the construction of the European Space Agency's rocket-launching base and a new town at Kourou in 1968, and by the adoption in the late 1970s of the Plan Vert (“Green Plan”), which encouraged increased agricultural and forestry production. However, overall economic gains were not enduring and did not eliminate high rates of unemployment, leaving many French Guianese dissatisfied with French administration; this frustration was intensified by the desire for greater autonomy or independence for the department. These two issues continued to be a source of unrest in the 1980s, '90s, and into the 21st century, evoking many protests and demonstrations.