The Great Eagle Spring is located southwest of the Kochbrunnen and Salm Spring at the Kaiser-Friedrich-Therme. It was already used by hunters in the Upper Palaeolithic period. In the Middle Ages, it was the bathing spring of the "Zum güldenen Adler" hotel. When the hotel was demolished in 1899, the spring came to the city of Wiesbaden. It was the first to be secured in 1954 with a 115 m deep drilled well. At a depth of 60 m, 70 °C warm thermal water emerged. Here, under 2.80 m of cultural debris, up to 5.54 m of stream gravel (with a sulphur gravel coating), sericite gneiss was found underneath. Stone tools and animal bones from the later Palaeolithic period (Gravettian) as well as relics from the Roman period were found in the cultural debris. A few meters southwest of the Große Adlerquelle is the satellite Kleine Adlerquelle, which is only 10.7 m deep. It is not used.