PINNACLES NATIONAL PARK (AP) — Officials on Monday celebrated the addition of America's newest national park.

Pinnacles National Park is a 27,000-acre expanse of volcanic rock and chaparral in Central California that spans San Benito and Monterey counties.

It has played a key role in the endangered California condor recovery project and is one of four release sites in the United States.

It's also a favorite of rock climbers drawn by its eponymous cliffs and rock spires.

The area was upgraded to national park status last month when President Barack Obama signed a bill making it the 59th national park in the U.S. and the ninth in California.

Rep. Sam Farr, D-Monterey, had worked for a decade on elevating the status of the park to give it permanent protections.

Farr co-sponsored a bill bestowing the national park designation in part to promote Pinnacles and help boost its attendance. As a monument, Pinnacles has had about 343,000 visitors a year, many of them rock climbers and bird watchers.

"Pinnacles was the missing book in the National Park Service's library, but today this geological and ecological wonder takes its rightful place on the shelf next to our nation's other great parks," Farr said.

Farr was joined at the ceremony by Interior Secretary Ken Salazar and other government officials.

Pinnacles National Monument was established in 1908 by President Theodore Roosevelt. National parks are established by Congress.

National parks tend to draw more visitors than national monuments. The park's east entrance is south of Hollister. The west entrance is near Salinas.