There are 63 National Parks. Thirty states and 2 territories, American Samoa and the US Virgin Islands, have National Parks. The number of states without a national park is 23. Many entities that aspire to National Park status are now National Monuments. Some will eventually become National Parks, like California’s Pinnacles did. Sixteen new National Monuments have been officially proposed.
New National Monuments, if accepted as National Parks, will mostly be in states that already have National Parks. There are currently 129 National Monuments. My favorite is Arizona’s remote Chiricahua. Four National Monuments have been proposed in California. The states that will have 2 new National Monuments are Utah, Arizona, Nevada, and New Mexico. There will be new ones in Montana, Colorado, and Oregon, which will share Owyhee Desert National Monument with Nevada if it becomes one. Some proposed National Monuments will be expansions of existing National Parks like Canyonlands in Utah and the Grand Canyon in Arizona.
It sometimes takes a long time for National Parks to be established, like the Gateway Arch. It officially opened in 1967 but did not become a National Park until 2018. The Lesser Prairie Chicken Preserve was proposed as a National Monument 11 years ago but it has not become such. To become a National Monument, an area must have the backing of a US President, must contain objects of historic or scientific worth, must meet the criteria of the Antiquities Act, and must be places already controlled by the Federal Government.
To become a National Park, an area must be recognized by an Act of Congress. However, US Presidents have the power to proclaim them on lands already under federal jurisdiction, like Ulysses S. Grant did when he created Yellowstone National Park in 1872. My sources for the above information are myself, tripsavvy.com, and 50states.com. The most recent National Monuments Ruth and I have been to for the first time are Newberry Volcanic near Bend, OR and Pipe Spring in northern Arizona. Both were worthwhile. The last National Park we visited for the first time was the eminently interesting Congaree in South Carolina that is seen up top.