Here are some stats about National Parks in the U.S. that I found from 10 different sources.
There were 237 million visitors and $941 million spent in 2021.
Alaska has the most park acreage with 54.7 million.
There are 63 parks with a total of 84 million acres.
Here is an infographic:
The least visited park was in Alaska called Gates of the Arctic.
Visitors logged 1.3 billion recreation hours in 2021.