The United States of America has large number of national parks and state parks. National parks can be accessed with an annual America the Beautiful National Park pass or per visit. State parks are controlled per state and have either annual pass for the particular state or a daily pass. One of my best experiences has been a Midwest selfdrive tour — combining an 8 day camping trip of Great Teton and Yellowstone National Parks.
I’ve been fortunate to work and travel widely in North America.