Yosemite National Park would grow by about 1,600 acres, its first expansion in 75 years, to shield its western boundary from potential development under legislation introduced in Congress on Tuesday.
Sen. Dianne Feinstein, D-Calif., who introduced the measure, said it would incorporate lands first proposed for inclusion in the park by conservationist John Muir.
"Yosemite is truly a national treasure," she said. "But Yosemite's popularity is also its greatest challenge. New development in Yosemite West would increase the threat of fire, habitat fragmentation and degradation of creeks that flow into the park."
Some 900 acres of the proposed addition have been purchased for preservation by the Pacific Forest Trust, and the owners of the remaining land have expressed a willingness to sell it to the National Park Service, Laurie A. Wayburn, the trust's president and chief executive, told the Los Angeles Times.
The proposed addition is on the park's western boundary, near the junction that takes visitors to Glacier Point.
Proponents say the legislation would be a fitting tribute to the park in advance of next year's 150th anniversary. In 1864 President Abraham Lincoln signed the bill granting Yosemite Valley and the Mariposa Grove, a stand of some of the world's largest trees, to the state of California as a public trust. Yosemite became a national park in 1890.
"It's nice to see legislators working together to make good things happen," Wayburn said.
The legislation, co-sponsored by Sen. Barbara Boxer, D-Calif., calls for the property to be acquired only through donation or purchase from willing sellers.
The proposal could run into trouble in the Republican-controlled House, which has resisted spending funds to expand parks at a time when Washington is awash in red ink and there is a backlog of unfunded park maintenance projects.
A similar Yosemite expansion bill introduced last year never got a hearing before the House Natural Resources Committee.
But the expansion recently received the backing of the California state Senate on a resolution introduced by a Republican, state Sen. Tom Berryhill, whose district includes the park.
The position of U.S. Rep. Tom McClintock, R-Calif., whose district includes the park, will be important. He was not immediately available for comment.
U.S. Rep. Jim Costa, D-Calif., who introduced a similar Yosemite bill in the House, called the measure critical to "preserving the integrity of one of our nation's most celebrated places."
Emily Schrepf, Central Valley program manager for the National Parks Conservation Association, said the bill would help protect habitat for wildlife such as Pacific fisher, Sierra red fox, Goshawk and Cooper's hawks, great grey and long-eared owls and wolverines.
Yosemite, the third most visited national park last year with more than 3.8 million visitors, is currently 761,266 acres.
The park service had no immediate comment on the legislation.
Explore further: Roaring success: lions return to Rwanda, with rhinos next?