Abby Sisk, of Ogden, Utah, was returning from a hike late Wednesday when the bear came out of the bushes near the gravel path where she was walking at the Kenai Princess Lodge in Cooper Landing.
A lodge guest heard screaming and looked outside, then ran to help Sisk and managed to scare the bear away, Alaska State Troopers spokeswoman Beth Ipsen said.
"It had her head in its jaws and it dragged her a few feet," Ipsen said. She said Sisk had major cuts to her face and head.
Witnesses told troopers at the scene that the grizzly was a very large male, up to 8 feet tall and 500 pounds to 800 pounds.
A spokeswoman at Providence Alaska Medical Center in Anchorage said Sisk was listed in critical condition. Sisk's mother was en route to Anchorage on Thursday.
Sisk started working at the lodge as a housekeeper in May.
"She's been having a good time, doing a good job," Lodge general manager Dan Michels said. "She's a great employee."
The lodge has told guests to use shuttles to the main lodge or walk in groups around the property. Several trails have been closed, including the one where Sisk was attacked.
Michels said no one saw any bear cubs nearby and staff members have no idea why the bear attacked.
"We're surprised this happened because this was so close to the lodge," Ipsen said.
Troopers have looked for the bear, but Ipsen said it proved to be a difficult task.
"We have reports of 25 brown bear in the area," she said.
"It'd be hard to figure out which bear was responsible for this."
The lodge's main building and guest accommodations are spread over 46 acres on the Kenai River. Cooper Landing is about 50 miles southwest of Anchorage on the Kenai Peninsula.
