Cilaos
Cilaos is a commune and highland village in the French overseas department of Réunion, located within the Cirque de Cilaos, a vast volcanic caldera at an elevation of about 1,200 meters in the island's southern interior. Covering an area of 84.4 square kilometers with a population of 5,215 as of 2022 (estimated around 5,100 as of 2025), it features a temperate, sunny climate and serves as a key destination for thermal spa treatments, traditional crafts, viticulture, and ecotourism amid dramatic canyons and peaks near the Piton des Neiges, the Indian Ocean's highest point at 3,069 meters.[1][2][3][4] Historically, Cilaos originated as a refuge for enslaved people, known as marrons, who escaped French colonial plantations on Réunion (then Île Bourbon) starting in the early 18th century, drawn to its isolated, steep-walled amphitheater for protection. The name derives from the Malagasy term tsilaosa, meaning "the place we never leave" or "where one is safe," reflecting its role as a sanctuary until slavery's abolition in 1848. Thermal springs were discovered in the early 19th century, transforming the area into a spa retreat with the development of thermal establishments in the 19th century and the opening of the Hôtel des Thermes in 1932, though full accessibility arrived only via a winding ~35-kilometer road from Saint-Louis, inaugurated in 1932.[5]) Today, Cilaos is celebrated for its cultural heritage and natural assets, including the Irénée Accot Thermal Spa, which harnesses mineral-rich waters for therapeutic benefits, and local specialties like jours de Cilaos embroidery, a delicate openwork technique displayed at the Maison de la Broderie. The commune produces Réunion's only wines at small vineyards showcased in the Maison du Vin, alongside renowned lentils, spices, and Creole cuisine available at its vibrant market. As part of the UNESCO-listed Pitons, Cirques and Remparts of Réunion, it offers extensive trails for hiking to sites like Mare à Joncs pond and the Roche Merveilleuse viewpoint, as well as activities such as canyoning in the Fleur Jaune and Bras Rouge gorges, mountain biking, and climbing on pitons like Piton de Sucre.[3][6][7]Geography and environment
Location and topography
Cilaos is a commune situated in the southern region of Réunion Island, an overseas department of France in the western Indian Ocean. It forms part of the Cirque de Cilaos, a large volcanic caldera shaped by ancient eruptive activity that created a dramatic natural amphitheater enclosed by steep basaltic cliffs rising sharply from the valley floor. This geological feature is characteristic of Réunion's shield volcano origins, with the cirque's rugged topography including deep ravines, canyons, and prominent pitons such as Piton de Sucre and Bonnet de Prêtre.[3] The commune's geographic coordinates are approximately 21°08′07″S 55°28′16″E, placing it centrally within the island's interior highlands. Covering an area of 84.4 km², Cilaos exhibits significant elevational variation, ranging from a low of about 380 m at its lower edges to a high of 3,071 m at Piton des Neiges, the island's tallest peak. This mountainous terrain contributes to a sparse population density of 61.8 inhabitants per km² as of 2022, as much of the land is steep and unsuitable for dense settlement.[1][8] Access to Cilaos is challenging due to its isolated position, primarily via the narrow, winding Route de Cilaos (D241), which ascends from Saint-Louis with over 400 hairpin bends through deep valleys and tunnels, offering panoramic views but requiring careful navigation. Alternative routes include paths over the central plateau, such as via Col de Bébour from the east, though these are more suited to hiking than vehicular travel. The entire area, including the Cirque de Cilaos, was inscribed as part of the Pitons, Cirques and Remparts of Réunion Island on the UNESCO World Heritage List in 2010, recognizing its outstanding volcanic landscapes and biodiversity.[9][10]Climate
Cilaos features a temperate highland climate classified as Cfb under the Köppen system, characterized by mild temperatures year-round due to its elevation of approximately 1,200 meters above sea level. The wet season spans December to April, with mild to warm conditions and high rainfall influenced by tropical cyclones and the southeast trade winds, while the drier season from May to November brings cooler, more stable weather with reduced precipitation. Annual averages, based on data from 1991 to 2020, include a mean temperature of 17.1°C, with maximums averaging 22.8°C and minimums 11.3°C, and total precipitation of 1,764.7 mm spread over about 90 rainy days.[11][12] The high altitude of Cilaos creates a distinct microclimate cooler than Réunion's coastal areas, where trade winds often condense into frequent fog and orographic rainfall upon encountering the cirque's steep topography. This results in persistent cloud cover and mist, particularly during the wet season, enhancing local humidity but tempering daytime warmth. Extreme precipitation events underscore the area's vulnerability; the 24-hour rainfall record is 1,825 mm set at Foc-Foc in Cilaos commune on 7–8 January 1966 during Cyclone Denise—a previous benchmark of 1,869.9 mm from 15–16 March 1952 at Cilaos is now considered erroneous.[13][14] These climatic patterns contribute to significant environmental impacts within the cirque. Heavy seasonal rains accelerate soil erosion on the steep volcanic slopes, posing risks to infrastructure and agriculture, while the consistent moisture and moderate temperatures foster rich biodiversity, including endemic plant species adapted to the humid highlands. The fog and rainfall support unique ecosystems, such as cloud forests, that thrive despite the erosion pressures from intense downpours.[15][16]History
Origins and settlement
The name Cilaos derives from the Malagasy term "Tsilaosa," translating to "the place one never leaves" or "a place of no return," which captured early perceptions of the cirque's isolation and inaccessibility.[3] This etymology reflects the site's role as a refuge, possibly linked to a Malagasy runaway slave named Tsilaos who sought shelter there during the era of enslavement. Prior to formal colonial settlement, the cirque of Cilaos served as a hidden sanctuary for escaped slaves, known as marrons, starting in the early 18th century. These fugitives, primarily of African and Malagasy origin, fled the island's coastal plantations during the height of the slave-based economy on Bourbon Island (now Réunion), seeking refuge in the steep, forested walls of the cirque to evade recapture.[17] Archaeological evidence from sites like the "Secret Valley" in Cilaos, dated to the late 18th and early 19th centuries, reveals seasonal camps used by these groups for hunting and survival, including hearths, tools, and remains of hunted birds and livestock.[18] Local toponyms in the region bear traces of Malagasy influences from these maroon communities, underscoring their cultural persistence amid resistance to enslavement.[17] The transition to permanent habitation began in the early 19th century, following the abolition of slavery in 1848, with the first documented settlers arriving around 1850. These early residents included mixed-race individuals—descendants of former slaves, indentured laborers, and European colonists—who established small communities drawn by the cirque's natural resources and relative seclusion.[19] The discovery of thermal springs in 1815 by local hunter Paulin Técher further catalyzed settlement, leading to the formal establishment of a thermal spa in 1839, which provided curative waters and attracted initial infrastructure development.[20] This facility marked Cilaos's emergence from isolation, fostering a nascent economy around hydrotherapy for colonists and locals alike.[21] By 1866, the population had grown from these modest maroon outposts to approximately 960 residents, reflecting steady influxes of families seeking land for subsistence farming and the spa's draw.[22] This expansion laid the foundation for Cilaos as a distinct communal entity.Modern developments
The commune of Cilaos was officially established on February 5, 1965, by decree, becoming administratively independent from the neighboring commune of Saint-Louis.[23][24] This separation marked the culmination of long-standing local demands for autonomy, transforming Cilaos into Réunion's youngest commune and enabling focused governance on its unique highland challenges.[25] Population growth in Cilaos accelerated through the 20th century, reaching approximately 5,735 residents by 1982 according to official census records, reflecting improved living conditions and economic opportunities.[26] Post-World War II infrastructure developments, including the completion of internal roads like the D241 linking Ilet à Cordes to central Cilaos in 1975, enhanced accessibility and supported this expansion by facilitating easier transport of goods and people.[27] A major setback occurred in January 1966 during Tropical Cyclone Denise, which brought record rainfall of 1,825 mm in 24 hours to the cirque, triggering severe floods that caused three deaths and widespread damage to homes, agriculture, and access routes.[28][29] Recovery efforts involved coordinated reconstruction by local and regional authorities, including repairs to the vital RN5 access road and reinforcement of riverbanks to mitigate future risks, underscoring the commune's vulnerability to extreme weather.[30] The inscription of the Pitons, cirques, and remparts of Réunion Island—including the Cirque de Cilaos—on the UNESCO World Heritage List in 2010 has bolstered preservation initiatives, promoting sustainable management of the area's biodiversity and landscapes.[31] This recognition has complemented a tourism surge since the late 1980s, driven by national development plans that highlighted Cilaos's thermal springs, hiking trails, and cultural heritage, drawing increasing visitors while integrating traditional embroidery as a promoted artisan draw.[32][33]Demographics and administration
Population trends
As of the 2022 census, Cilaos has a population of 5,215 inhabitants, yielding a density of 61.79 inhabitants per square kilometer over its 84.4 km² area.[1][2] As of January 1, 2025, the estimated population is 5,122.[4] The population has experienced notable fluctuations over recent decades, generally declining since a peak in the late 1990s amid broader migration trends tied to the tourism-driven economy and outward movement to urban centers. Historical census data illustrates this pattern:| Year | Population |
|---|---|
| 1968 | 5,586 |
| 1975 | 5,672 |
| 1982 | 5,735 |
| 1990 | 5,856 |
| 1999 | 6,115 |
| 2006 | 5,838 |
| 2011 | 5,623 |
| 2016 | 5,403 |
| 2022 | 5,215 |