This morning’s Mercury News covers President Obama’s signing of legislation that gives official wilderness protection to 2.1 million acres across the United States.

With Obama’s signature, wilderness designation was extended to roughly 750,000 acres of federally owned land in California, including Mineral King Valley in Sequoia-Kings Canyon National Park, where Walt Disney attempted to build a massive ski resort in the 1960s; bristlecone pine forests in the Eastern Sierra, and vast expanses of desert, including portions of Joshua Tree National Park.

In wilderness areas, people are allowed to hike, ride horses, camp, hunt and fish. But logging, mining, building roads and riding mountain bikes is banned in such areas. Roughly 109 million acres — or 5 percent of the United States — is federally protected wilderness.

Alas, no Bay Area sites, but the decision affects something dear to all our hearts: the water supply. The law will restore a significant stretch of the San Joaquin River, which feeds the California Delta, which supplies about half of our drinking water.

For backpack trip planners, here’s GORP’s page on Mineral King Valley and some pictures of the valley at Flickr.