(Updates with fire burning inside Yosemite)
By Laila Kearney
SAN FRANCISCO, Aug 23 (Reuters) - A wildfire raging in Northern California has burned into Yosemite National Park, a park spokeswoman said on Friday, as the blaze threatened one of the state's most popular tourist destinations and resisted firefighters' efforts to control it.
The so-called Rim Fire, which exploded in size overnight to become the fastest-growing of 50 large wildfires burning in the U.S. West, had blackened 11,000 acres at the northeastern edge of Yosemite as of Friday, park spokeswoman Kari Cobb said.
The flames had reached Lake Eleanor, a small lake accessible by hiking trails and normally open for fishing and swimming, Cobb said.
"Its not a very visited part of the park, even though it is very beautiful," she said, adding the blaze was about 4 miles west of Hetch Hetchy Reservoir and some 20 miles from Yosemite Valley, the park's main tourist area.
Park officials earlier this week closed Lake Eleanor, Hetch Hetchy, and the Hodgdon Meadow Campground to the public as a precautionary measure.
There were no immediate plans to close additional areas of the park or ban access to Yosemite as a whole.
"We're not anywhere near closing the park," Cobb said. "We have to wait and see what the fire activity is and what it does, and we're just going to try as hard as we can to help with the suppression of the fire."
The 105,000-acre Rim Fire, named for a Stanislaus National Forest lookout point called Rim of the World, has destroyed four homes and 12 outbuildings since it broke out on Saturday.
Only 2 percent of the fire was contained as of Friday, and firefighters were concentrating on protecting homes and communities, fire information officer Ashley Taylor said.
"Firefighters are still going to have a stressful situation out there," Taylor said of the blaze, which was burning in rugged, remote terrain. "We are just expecting a very active fire."
California Governor Jerry Brown has declared a state of emergency in Tuolumne County, where the fire is burning.
Additional evacuation orders have been given for more homes near the burn zone, and another 2,000 homes were now considered under threat, up from 2,500 on Thursday. Taylor could not say how many people were affected by the orders.
Until now, the evacuation orders have included at least 19 recreational areas in Stanislaus National Forest, among them campgrounds and recreational vehicle campsites. Two evacuation centers have been set up for people displaced by the fire.
The National Park Service said that Highway 120, which leads to the west side of Yosemite, was temporarily closed. It is one of four access routes to the park. The cause of the Rim Fire is under investigation.
Yosemite National Park, famous for its waterfalls, giant sequoia groves and other scenic wonders, covers 750,000 acres (300,000 hectares) and supports a highly diverse animal population.
The park, which is 195 miles from San Francisco and 315 miles from Los Angeles, attracted nearly 4 million visitors last year. (http://www.nps.gov/yose/index.htm) (Writing by Cynthia Johnston and Dan Whitcomb; editing by Toni Reinhold and Matthew Lewis)