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Big Hollow is a 40-square mile wind deflation basin scoured out by high winds during a prehistoric dry period. The hollow represents a classic case of "topographic reversal" and is the largest demonstrable example of its type in the 48 contiguous states. The site has typical natural wind-swept high altitude vegetation and examples of salt- and selenium-tolerant species.
Location: Albany County, WY
Year designated: 1980
Ownership: Federal, Private
Please remember, National Natural Landmarks (NNLs) are not national parks. NNL status does not indicate public ownership, and many sites are not open for visitation.
Last Updated: June 28, 2012