The 65 official national parks contain 52 million acres of land, about 2% of the total U.S. land area (2,430 acres).

A complete break down of the US National Parks by Size – National Park Obsessed

There are 423 national park “areas” accounting for 85 million acres in total (3% of U.S.).

Frequently Asked Questions (U.S. National Park Service) (nps.gov)

NPS-Acreage-9-30-2020.pdf

National park system areas continue to be added each year.

Park Anniversaries – NPS Celebrates! (U.S. National Park Service)

National Park Visitors

Year	Visitors (M)
2019	328
2010	281
2000	286
1990	256
1980	220
1970	168
1960	72
1950	33

Annual national park visitors count has increased ten-fold in 70 years.

Visitation Numbers (U.S. National Park Service) (nps.gov)

State parks contain another 14 million acres. State parks had 807 million visitors in 2017, more than two and one-half times the national parks, despite their smaller areas. In total, that’s 1.1 million annual visits or 3.4 for each of the 330 million U.S. citizens. Between 1984 and 2017 attendance has increased by 30%.

Parks and Recreation in the United States: State Park Systems (rff.org)

Attendance trends threaten future operations of America’s state park systems | PNAS

During the pandemic, state parks attendance increased significantly, although national parks attendance fell due to mandated closures.

Summertime Visitors Swarm State Parks and Budgets | The Pew Charitable Trusts (pewtrusts.org)

Data for local (county and city) parks is not readily available. One summary shows more than 2 million acres of “city” parks in selected major cities.

CityParkFacts_2017.4_7_17.FIN_.LO_.pdf (tpl.org)

Parks and Recreation in the United States: Local Park Systems (rff.org)

My experience in Indiana, Ohio and Illinois indicates that the total “local” parks acreage is at least twice as great as this indicator. For example, 42 of Ohio’s 88 counties have a parks district.

Parks and Natural Areas – (ohiobiota.com)

There are an additional 56 million acres in voluntary land trust conservation areas. While these areas often have limited access and improvements, they served another 6 million visitors in 2015.

56 Million Acres Voluntarily Conserved in America, National Land Trust Census Reveals | Land Trust Alliance

The Nature Conservancy: A World Where People & Nature Thrive

Home Page | ACRES Land Trust

The total federal, state, local and private “parks” areas equals 161 million acres, nearly 7% of the total U.S. land area.

Federally managed forests contain 238 million acres and state forests contain 83 million acres. Most of these lands provide significant access for hiking, hunting and riding. At 321 million acres, they represent 13% of the total U.S. land area.

Forest Ownership Statistics – National Association of State Foresters

Grand total of 482 million acres of parks and forest lands, fully 20% of the U.S. land area.

This has nearly all been created since 1900.

History of the National Park Service – Wikipedia