President Biden on Thursday signed a proclamation expanding the San Gabriel Mountains National Monument and the Berryessa Snow Mountain National Monument, protecting nearly 120,000 acres of land in California.

A White House official said the act will help preserve an area that is rich in historical and ecological significance and is within just an hour’s drive of 18 million people.

It also would increase the monuments by roughly a third, extending the San Gabriel Monument’s boundaries to the back door of San Fernando Valley neighborhoods, including Sylmar, Santa Clarita and Pacoima.

---

---

It will also give the U.S. Forest Service the greater ability to protect natural resources in areas left out of the 2014 monument designation by President Obama.

Mr. Biden’s proclamation would add and protect 105,919 acres of land in the San Gabriel Monument and 13,696 acres in the Berryessa Snow Mountain National Monument.

“These expansions will increase access to nature, boost our outdoor economy, and honor areas of significance to Tribal Nations and Indigenous peoples as we continue to safeguard our public lands for all Americans and for generations to come,” Vice President Kamala Harris said in a statement.

The designation also protects an 11-mile-long north-south ridgeline that is sacred to the Patwin tribe and home to a mosaic of rare natural features supported by the area’s unique geological features.

Rep. Judy Chu and Sen. Alex Padilla, both California Democrats, sent a letter to Mr. Biden last year and asked him to bypass Congress and issue a proclamation expanding the monuments under the Antiquities Act of 1906.

The law empowers presidents to create national monuments on federal land and protect “objects of historic and scientific interest.”

The lawmakers said Mr. Biden needed to act quickly because a package of conservation bills, which would include expanding the monuments, had been held up in Congress.