The Cupatitzio River, named for the Purépecha language term for "singing river," cuts through the city of Uruapan, dramatically carving its grounds. Nowhere is this clearer than in the canyon that defines this national park. Near its northern end, you can find The Devil's Knee, the spring from which it is said the river is born.

The dramatic name of this spring originated from a legend that says that the devil was exorcised from this place by the priest Juan de San Miguel in the 16th century. Running away from the scene, the devil tripped, and upon hitting the ground, his knee broke the earth and water sprang forth.

The Cupatitzio's waters flow southward from here over other waterfalls in the park and feed the trout farm located in it. The state of Michoacán was one of the first in Mexico where modern aquaculture began being practiced. With rainbow trout as its flagship species, and one of the state's better-known foods, it makes sense that such a fresh water source would be destined for this farming.

The farm is accessible as part of the park, and fresh fish can be bought from it. This represents part of the national park's interesting culinary offers. Food stalls along its main path offer roasted quail in addition to usual Mexican street food fare and drinks like lechuguilla (a slightly fermented, sweet agave juice pre-packed in a plastic bag) and "pico de gallo water" (sharing the chopped produce and spicy aspects of the homonymous salsa, but being a sweet fruit concoction instead).