It is a saltwater lagoon with a length of 31.8 kilometers, and an average width of 5.3 kilometers that is considered a bird sanctuary.

You can find a wide variety of migratory birds such as: snow goose, Canada goose, American stork, Canadian swallow, freshwater seamstress and white pelican, among others.

During the summer and autumn the lagoon is full mainly of rainwater and in winter and part of spring the lagoon dries up..

In pre-Hispanic times it was one of the sources of salt, so it was very important.