The park was established as part of the Ecuador national parks system in 1970.

Volcan Cayambe has a permanent snow cap and a glacier on its eastern flank. It is an active compound volcano that last erupted in 1786. It is a popular destination for mountain climbing. The route to the top is moderately difficult at lower elevations but becomes challenging in the final stages where climbers must cross a glacier and navigate numerous cracks and fissures, cope with seracs, and climb a steep section with inclines over 45°. A mountain hut called the Ruales-Oleas-Bergé Refuge supports climbers preparing to ascend Cayambe. The park has a number of waterfalls along its mountain streams and rivers, most famous is the Cascada San Rafael, once a popular scenic spot for shutterbugs though the waterfall actually collapsed on itself in 2020 due to forces of the rushing river waters.

The park is a hotspot of biodiversity with more than 100 species of endemic plants, dozens of species of mammals, a whopping 900 species of birds, 140 reptiles, and 116 amphibians. The large number of species is a product of its range of diverse ecosystems with sparse, cold mountain conditions in the highlands, areas of páramo and montaine forests as the mountains give way to lowlands, and hot humid rainforests that support jungle animals like monkeys and tropical birds.

Mammals include the endangered spectacled bear in the rocky highland areas of the park and several species of monkey lurking in the trees in the tropical jungles of the northeast section of the park. Another interesting endangered mammal found in the park is the Andean tapir, which is the only species of the tapir family that does not live in tropical jungles. The Andean tapir is similar in size and shape to its lowland cousins, but can be distinguished by its thick fur coat.

More than 200 bird species in the park entice many Birdwatchers to grab their binoculars for a birdwatching hike along the park's many trails. Interesting birds include the famous Andean condor as well as an odd avian predator called the variable hawk, which gets its name from its range of different colorations and forms that it might take. Sometimes the bird appears mostly black, while in other forms it can take on a mottled look resembling the coloration of a calico cat.

From Quito you can get to Cayambe by bus. Cooperativa Flor Del Valle operates frequent buses (about every 15 minutes), departing Quito from Terminal la Ofelia. The fare is about US$3 for the 90-minute trip.

To Santa Rosa, Cooperativa de Transportes Loja Internacional operates buses departing the Terminal Carcelen toward Carlamanga, which is beyond Santa Rosa. Tell the driver you want to get off at El Chaco, which is about 5 km from Santa Rosa. You can take a local taxi to the town. The bus will cost about US$10 for the 2-hour trip.

There is not a direct bus to Papallacta but you could take a bus from Terminal Terrestre Quitumba as far as Pito (less than half way). From there, you would need to take a taxi the rest of the way, so it's probably easier to just take a taxi all the way from Quito to Papallacta (or rent a car or SUV).