Last updated: April 17, 2025
Article
Visit Astonishing National Natural Landmarks
National Natural Landmarks (NNLs) are natural areas that contain significant examples of the nation's biological and geological features. The 600+ NNLs are designated by the Secretary of the Interior as the best examples of a type of biological community or geological feature. The National Park Service works cooperatively with landowners, managers, and partners to conserve these sites.
Since NNLs are relatively unknown compared to more popular park sites, they can sometimes serve as less busy alternatives. However, NNL status does not indicate public ownership and each NNL is managed differently. Some may not be open to the public. So, it's important to know before you go and research the site before your visit.
If you need a starting point, the following are some of our favorite NNLs that are open to the public and have some amazing natural features!
If you need a starting point, the following are some of our favorite NNLs that are open to the public and have some amazing natural features!
Hidden Gems
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OregonFort Rock State Natural AreaFort Rock, formed 10–12K years ago, is a tuff ring created by volcanic explosions beneath a lake, later eroded into its crescent shape.
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WashingtonGinkgo Petrified Forest State ParkHome to North America's most diverse Miocene petrified wood site with 40+ wood types, plus Ice Age Flood features that shaped the land!
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FloridaCorkscrew Swamp SanctuaryWalk the boardwalk to discover a living treasure trove of biodiversity & the largest remaining old-growth bald cypress forest in the South.
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North CarolinaStone Mountain State ParkDiscover a massive granite monadnock with rare, endemic plants—perfect for exploring geology, unique habitats, and scenic views.
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TexasCaverns of SonoraCoralloid growths (cave popcorn) & bladed helictites are just some of the rockin’ formations that await visitors to this underground wonder.
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ArizonaBarringer Meteor CraterWhat does it look like when a 150-foot-wide iron-nickel space rock (aka meteor) hits Earth? Check out this northern Arizona crater to see!
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PennsylvaniaCook Forest State ParkExperience the towering pines and hemlock of the Forest Cathedral in this relict, old growth forest in northwestern Pennsylvania.
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ConnecticutDinosaur State ParkJourney to the early Jurassic and view 200-million-year-old fossil dinosaur footprints right in central Connecticut.
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MinnesotaCedar Creek Natural History AreaHelen Allison Savanna Preserve - Discover an internationally famous landscape where forests, prairies & wildlife meet.