Maria's spring, Mineral spring in Mariánské Lázně, Czech Republic.

Maria's Spring is a mineral water source located at about 650 meters elevation on the grounds of Hotel Maria Spa. The water has a specific mineral composition that sets it apart from other local sources.

The spring gave Mariánské Lázně its name and was the first source used there, before the town was founded. Around 1786 a log building with four baths stood on the site; J. J. Nehr had the first spa house built here, and in 1812 the Old Baths were constructed nearby. In 1977 the wooden pavilion was demolished and gas was captured from a 52-metre bore.

The spring gave Mariánské Lázně its name: a picture hung on a tree by a wandering soldier who treated himself with the waters, from which the town's name derives. The gas is still used for injection therapy and dry gas baths for heart conditions.

The spring's gas is captured in the courtyard of the Old Baths, and the pavilion there is closed to the public. Patients use the gas at Hotel Maria Spa, about 100 metres from the BJ-6 Nová Marie borehole on the slope. The water is piped to the bottling plant above the Ferdinand Spring colonnade.

The spring was long overshadowed by other local sources but is increasingly valued for its distinct mineral profile. This makes it of interest to visitors curious about the differences among the area's mineral waters.