Photo by Renamed user 24ae73ffaaed757c266ab142215896cb, via Wikimedia Commons (CC0)
🇵🇹 Portugal · Azores, São Miguel Island
Photo by Renamed user 24ae73ffaaed757c266ab142215896cb, via Wikimedia Commons (CC0)
🇵🇹 Portugal · Azores, São Miguel Island
♨ Temperature
98°C
⛰ Altitude
280 m
⚗ pH
4.2
💧 TDS
2100 mg/L
🌊 Flow rate
35 L/s
📅 Established
16th century
✓ Verified on 2026-07-22
The volcanic caldera of Furnas on São Miguel Island contains one of the most diverse arrays of spring types anywhere in the world — boiling sulphur caldeiras, cold iron-rich ferruginous springs, carbonated waters, and hot mud pools — all within a small valley. The area is famous for cozido das Furnas, a traditional meat stew cooked underground by geothermal heat. The hot springs flow into the shores of Lagoa das Furnas and are used for therapeutic bathing.
| Sulphur (H₂S) | 8.4 mg/L |
| Iron (Fe²⁺) | 9.8 mg/L |
| Carbon Dioxide | 1600 mg/L |
| Bicarbonate | 780 mg/L |
| Sodium | 340 mg/L |
The Furnas valley was first documented by Portuguese settlers in the 16th century. The historic Parque Terra Nostra — one of the finest botanical gardens in the Atlantic — was established around the spring pools in the 19th century and is classified as a Portuguese national monument. The Lagoa das Furnas lake, fed by springs, is a protected Natura 2000 site.
Furnas is the home of cozido das Furnas — a traditional stew buried underground in volcanic soil and slow-cooked for six hours by geothermal heat. This centuries-old practice of geothermal cooking is a living cultural tradition that defines Azorean identity. The Azores' volcanic landscape has shaped a culture of resilience, adaptation, and deep respect for natural forces.
The Lagoa das Furnas is at the centre of a major ecological restoration project — the Biosphere Reserve Azores has implemented constructed wetlands and riparian buffer strips around the lake to reduce agricultural runoff and preserve the spring ecosystem. The Azores are classified as a UNESCO Biosphere Reserve, and geothermal energy development is carefully managed to ensure spring flows are not disrupted.
Phone+351 296 584 622
Websitewww.azores.gov.pt
AddressFurnas, Vila Franca do Campo, São Miguel, Azores