Warm Mineral Springs in Florida is the largest warm mineral spring in the world. The spring is about 1.5 acres in circumference and reaches a maximum depth of approximately 250 feet in its center.
Warm Mineral Springs is located in North Port, Fla., along the state's west coast. The average year-round water temperature of the spring is 87 degrees Fahrenheit. Warm Mineral Springs has been a popular spa destination since the 1960s, and it was added to the U.S. Register of Historic Places in 1977. The spring is a large sinkhole that was formed in carbonate rock thousands of years ago.