The US national parks with the most plant and animal species

The sky is broad, the land is rugged and the air fills your lungs with joy. But for many adventurers, the true appeal of a trek through a national park is the fine detail: the living flora and fauna, often rare and unusual, that quietly populate the landscape.

U.S. national parks are each home to an average of 415 species of wildlife. Each species plays an essential role in the park's ecosystem, and each park has its own unique characters, sights and sounds. From tiny but tough pikas to trumpeter swans and Dutchman’s breeches, these wild expanses are full of surprises.

So, if you were going down to the park today, which parks would you be most likely to run into a surprise?

Casago analyzed National Park Service data to find out which parks have the most wildlife and plants per 100 km² and which have the greatest biodiversity overall.

Key Findings 

• Congaree in South Carolina has the greatest density of wildlife species, with 362 per 100 km².
• However, Biscayne in Florida has more overall: a total of 1,002.
• Carlsbad Caverns in New Mexico boasts 194 bird species per 100 km², the highest density.
• Cuyahoga Valley in Ohio has the densest plant biodiversity of all, at 935 species per 100 km².
• The Great Smoky Mountains in North Carolina and Tennessee have the highest number of plant species overall: 2,278

Methodology 

Casago sourced all the national parks in America with their coordinates from Wikipedia. For each park, the team then downloaded detailed records of all species present from irma.nps.gov and park area sizes from Parks Expert. 

For each park, Casago extracted the number of amphibians, birds, fish, mammals, reptiles and vascular plants by counting records of approved species that fell under any of the six categories. The numbers of amphibians, birds, fishes, mammals and reptiles were combined to get the total number of animals and vascular plants to get the total number of plant species. 

To get the density of species, Casago calculated wildlife species (all five categories of animal species), bird species and vascular plant species per 100 km² for each park. Parks with less than 100 km² area were excluded from further analysis. 

The data was collected in February 2023.