For the more information about the air resources of the National Park Service, please visit http://www.nature.nps.gov/air/.
Portland Arch Nature Preserve
Portland Arch Nature Preserve contains massive crossbedded sandstone cliffs and a seven-foot high natural bridge. The site has many plant species unknown elsewhere in Indiana, some of which are relicts occurring due to the unusual climate created by the canyon.
Location: Fountain County, IN
Year designated: 1973
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