Salazar said in an Interior Department release Thursday's 45th anniversary of the 1964 federal measure and the National Wilderness Preservation System reflects a significant step forward in U.S. conservation efforts.
"The creation of the National Wilderness Preservation System is one of the greatest events in the history of American conservation," Salazar said. "These pristine places that are set aside to be forever wild and untouched inspire us and remind us of the bounty with which our nation is blessed in the beauty and richness of our land."
Undeveloped federal lands free of human habitation and development are protected as wilderness areas under the federal measures. Such sites are managed so their natural conditions remain in place.
The act's anniversary comes months after the Omnibus Public Land Management Act of 2009 was signed into law by U.S. President Barack Obama. The March signing designated an addition 52 U.S. areas as official wilderness areas, while increasing the acreage of other wilderness sites.