Mono Basin
National Scenic Area
(USFS)
California
California
Inyo National Forest
Inyo National Forest
U. S. Forest Service
U. S. Forest Service
Official Site: https://www.fs.usda.gov
Wikipedia: https://en.wikipedia.org/wiki/Mono_Basin_National_Scenic_Area
While, apparently, Mono Basin is now considered a National Scenic Area (according to Wikipedia, at least), it was designated as a National Forest Scenic Area in 1984. Because of this, the Columbia River Gorge National Scenic Area, established in 1986, is considered the first, true National Scenic Area.
From Wikipedia:
Mono Basin became the first National Forest Scenic Area in the United States in 1984.