El Dorado Springs was founded around this spring in 1881 because of the water's medicinal value. A stone above marked its first site 75 ft. to the SE until 1890, when the spring was routed to this basin. During repairs in Sept. 1992, a sandstone slab was found covering an unknown manhole and tunnel built in 1906, the date of the last major repairs. To maintain the spring's historic integrity, this slab replaced the 1906 stone, which is now on display at the museum.