A dog couldn't have picked a worse place to get lost than the countryside south of Mount Airy, Md.

The houses are few and far between; the fields so thick with corn an animal could hide until Thanksgiving.

Montgomery, Frederick, Howard and Carroll counties converge there, and an anxious owner in search of a lost pet has to keep calling or visiting not one but four busy, far-flung animal control shelters. Montgomery's pound alone gets 400 calls and takes in an average of 35 animals every day.

So when Baltimore residents Cindy Spitzer and Michele Naar learned Aug. 18 that their 7-year-old mixed German shepherd Chelsea had bolted from a kennel south of Mount Airy, they began a frantic, night-and-day, and thus far fruitless, search.

But residents of the four counties, stirred by the persistence of two women willing to tramp the woods in the dark and hand out 2,000 fliers door to door, have rallied to help find Chelsea over the past two weeks, and the search for her has spread over a five-mile area of central Maryland.

Some of Mount Airy's children have joined in the search. Kristin Gordon, 11, spent her allowance on dog food, set out by bicycle for a whole day looking for Chelsea -- and her bike wound up with two flat tires in the process. The sixth grader, who attends Howard County's Glenwood Middle School, biked along the roads over five days, stopping at stores and questioning shoppers and owners, her mother said.

"We were crying and hysterical," Spitzer, a University of Maryland graduate student and free-lance writer, said of their first night's vigil in the Mount Airy woods. Chelsea has been reportedly sighted a number of times in upper Montgomery, most recently on Saturday, but is still on the lam.

Spitzer, who is working on a degree in science journalism, and Naar, a pathology graduate student, have left articles of clothing in people's yards to encourage the dog to stick around. They begged the last of the area's trackers of domestic animals into coming out of retirement and searching the area with her dog team. They are about to begin another round of flier distribution.

Seventy to 80 people, many from the Damascus area, have called Spitzer to report that a mixed shepherd has been spotted. Only one caller mentioned the $300 reward, she said, and the rest treated the notion of accepting the money with disdain.

Spitzer and Naar, who had left the dog at the Belquest Kennels during a four-day camping trip, said they have exhausted their funds in the search and have had to borrow to pay this month's rent. But they were still talking last week about trying to rent a helicopter.

Chelsea has joined the ranks of the missing in Montgomery County, which said it locked up 5,288 stray dogs in the past fiscal year, along with 1,756 cats. Two-thirds of the stray dogs but only 15 percent of the cats were reunited with their owners, said Mary Eno, education director of the county's humane society, which operates the shelter.

Chelsea "could be anywhere" in that broad, rural four-county area, said a spokeswoman for Rescue, one of several private animal rescue organizations in the Washington area. These groups help in the search for individual breeds and give advice to owners of mixed breeds as well.

Meanwhile, the kennel that had cared for Chelsea for 3 1/2 days also has circulated fliers and is getting calls, said owner Vicky Creamer. Dozens of residents continue to search along roadways and in woods.

Chelsea was a refugee of the streets of Brooklyn and a battered dog when Spitzer found her near Jones Beach six years ago. The dog is still so frightened of the world that she will respond only to her two owners, they say. Spitzer said Chelsea can be caught only by coaxing her with food.

"She's an extremely shy dog, very sweet, very gentle," Spitzer said. "For a German shepherd, she's very shy. She's afraid of everything: squirrels, other dogs . . . . People try to go up and touch her and she runs away . . . . She doesn't know the first thing about cows and corn." The dog ran off, minus her collar, when a kennel employe took her outside to dry after a bath, Spitzer said.

"I've never seen anyone pursue anything with such vigor," said boat dealer David Reed, who lives on the outskirts of Mount Airy in Frederick County and who has helped Spitzer, 33, and Naar, 31, by looking along the highways.

The spokeswoman for Rescue said Spitzer and Naar have followed all the steps recommended to owners of lost dogs. Among other things, they have:

Called the shelters.

Checked with service people such as mail and newspaper carriers who are out when neighbors may not be.

Checked the classified ads and taken out ads of their own. Some papers, including The Washington Post, will publish free ads for people who find strays.

Posted fliers, preferably in attention-getting colors such as yellow and bright blue.

The best thing to do, the groups said, is to make sure your dog is kept inside when there is no one at home.

Dave Reed, who said he looks along the highway for Chelsea as he drives to and from his boat dealership, said that one result of the search is that "I now have a dog I didn't want . . . .

"I found this German shepherd in the road, so scared it couldn't move, sick and wet from the rain. I said to myself, 'Boy, will they be happy that I've found their dog.' The dog and I went and pigged out at McDonald's."

But when Spitzer went to retrieve it, she said, " 'You're such a nice man, but that's not my dog,' " recalled Reed, who formerly owned two fence-jumping Labrador retrievers and had vowed never to get another animal. "I guess we'll just keep it," he said of the stray. "I haven't got the heart to take it to the pound."