DOWNEAST MAINE pushes its head well up into what otherwise might D be Canada, a land drenched in fog and innocent of the sandy beaches of southern Maine. Rte. 1, so choked with fast-food restaurants and gas stations farther south, is a two-lane road here, winding through evergreen trees that hug its ditches and rocky fields on which nothing can grow. This bleak, wild landscape has attracted summer people whose roots go generations back.

"We don't call that Maine," said a summer resident of Ellsworth recently, on being introduced to a devotee of Kennebunkport and Old Orchard.

This is the Maine of E. B. White and of Mary Ellen Chase, whose white frame house is just off the road in the tiny village of Blue Hill. It's the Maine of lobster and bean suppers hosted by the ladies of the Congregational and Unitarian churches in myriad small villages, and of the sheer rugged beauty of Acadia National Park on Mount Desert Island. For much of this we have to thank John D. Rockefeller Jr., who ventured north to Bar Harbor when his son Nelson was born, fell in love with it and donated a third of the park's land.

A fascinating glimpse into early Bar Harbor, before the disastrous fire of 1947 that destroyed so many of the summer cottages and hotels, is preserved today in the little museum in the bowels of the Bar Harbor library. Rockefeller's letter explaining how he came to this rocky land is framed on the counter, preserved along with wonderful old newspaper clippings of the seasonal arrivals and departures of the smart set and reports of their parties and of the terrible fire. The everyday things hidden away under the glass counters are somehow unaccountably touching. Among other treasures is a splendid old tintype of an 1871 hiking group, subtitled "manhood in the making," flanked by an ancient timetable of the Maine Central Railroad and a can of sperm sewing machine oil.

Bar Harbor and Mount Desert were discovered in the mid-19th century by the fashionable who wearied of Newport.

"Mount Desert is a jolly place," wrote S. Meir Mitchell, a Philadelphia doctor, in 1860 to his sister. "Two miles long, ten broad, mountains in the middle: eight lakes between them; sea wall all around."

Mitchell was one of the early arrivals and shortly was followed by a flock of the rich, who arrived with platoons of servants, tennis rackets and plenty of tinned delicacies to piece out native fare, and prepared to "rusticate." In Bar Harbor, they built mansions they called cottages, thinking nothing of 24 bathrooms with gold fixtures or a private heating plant, and lighting their parties with offshore flood lights from their yachts.

The list of Bar Harbor cottagers at the turn of the century reads like a roster of American millionaires--John D. Rockerfeller, A. Atwater Kent, Joseph Pultizer--but the Depression and World War II changed even their way of life. Their cottages were left with caretakers; some eventually were demolished and others later destroyed in the great fire. The simple life on a grand scale, as Kent called it, vanished with few traces. What remains for 20th-century visitors to this part of Maine is the epic grandeur of the scenery that drew the first visitors. The mountains, the rocky sea walls and the stunning austerity of the shoreline is as unspoiled today as it was when those wealthy predecessors discovered it.

Bar Harbor is no longer "a rather wild place where girls from New York and Philadelphia walk up mountains swinging their arms," as one 19th-century Boston matron thought of it, but Acadia Park, at least, remains forever untamed. The view from lofty Mount Cadillac across Frenchman's Bay is frequently compared with the Bay of Naples and, if there is a wilder, more majestically lonely place than Schoodick Point, so beloved of gulls, it's hard to imagine where. The crowds don't seem to have found Acadia. Maybe it's too far off the beaten track, too far from the big cities, too inaccessible. Chances are if you want to go berry picking, you'll have only a cormorant or two for company.

Back in the 1890s, Jordon Pond House at Seal Harbor was the place to go for lunch or dinner, and it still is. So loyal are its admirers that when the restaurant burned down in 1979, private funds were hastily assembled to build it back as much as possible the way it was. Gray shingled and hugging the land, it serves a splendid lobster, and its popovers and homemade ice cream are justly famous.

To see the real downeast Maine, canny visitors scan the library and post office bulletin boards for announcements of community suppers. By 5 p.m. on the nights when one is scheduled, church parking lots fill up quickly with cars and licenses from places like Florida and Colorado, and people "from away," as they are known, eat at long tables with people "from around here." The good ladies of the church are busy cooking and serving, but the man beside you may have sold them the lobsters direct from his boat or come direct from the blueberry raking fields. This may be the one place an outlander can eat all the lobster he wants and afterwards, like as not, there'll be a painting to raffle off to fatten the church coffers.

Summer roots are taken seriously in this part of the world. The same families have been coming back for years to places like Winter Harbor and posh Grindstone Neck. Maybe because these summer residents are fiercely loyal to Maine, the proverbially wry taciturnity of Mainers is missing in this part of the state. Drop in to J. M. Gerrish's drugstore in Winter Harbor and have a Winter Harbor beer at the counter--a pale yellow mixture of vanilla and coffee syrup and sparkling water, no ice--and everybody will be as friendly as if they've always known you. Mrs. Clark, who tends the fountain, will tell you about her new L. L. Bean snow pants, and the mailman, dropping in for a drink himself, will stop a while to talk about the Maine winters.

This kind of soda fountain cum general store is a fixture in all the villages of downeast Maine, picture postcard villages hugging picturesque harbors and each clustering close to a little white church lifting a spire to the foggy sky. The sea, so dominant here, is hard on paint, and often the houses are in dire need of a fresh coat. In Ellsworth, the elders tired of the annual expense of painting the Congregational Church and now its spire is fiberglass, but you can't tell the difference. Across the way, the Ellsworth Library, an early 19th-century beauty that was once the home of the first collector of the port of Frenchman's Bay, is well kept, perhaps because of its listing on the Historic Register. Ellsworth, the center for the area, looks like any of the more southern New England villages until you see the sign on the factory at the entrance to town, "We cut moose."

On the western crab claw of mainland that includes Mount Desert Island in its pincers, is Blue Hill, the 1762 settlement where loving care has preserved many things lost elsewhere. Summer money and town cooperation have saved the elms that in most New England villages have turned to sad vase-shaped skeletons and preserved the old houses that give the town its character. Not the least of Blue Hill's efforts to save the past is the Parson Fisher house, built in 1797 by Jonathan Fisher, fresh out of Harvard and eager to undertake his first assignment in the ministry.

The house inside is spare and bare as the Congregational faith Fisher embraced and, since he was making $200 a year, a triumph of ingenuity. Surely there never was a more industrious man at adding to his pitiful pittance. He farmed, concocted medicinal remedies from herbs in his garden, sawed buttons from the bones of his dead household pets, painted names on sleighs ($2.50 each) and still found time to make his own furniture, including a wooden clock that uses a broken wine glass as a striker. In his spare moments, Fisher wrote and beautifully illustrated several books for the edification of his four daughters, and four times a year skated up to Bangor, 70 miles round trip, on churchly matters. He also was a rather skilled artist.

The parson's 20th-century neighbor, Mary Ellen Hase, celebrated this part of downeast Maine in her books. E. B. White chose nearby Brooklin for his year -round home and lives there to this day. "I like living in Maine the year round," he once wrote. "It gets me pleasantly out of touch with all the things well worth being out of touch with." Like White, the people from away keep returning until the feel of the place gets into their blood and, standing on those rocky seawalls watching the sea hurl its salt fume, it's easy to understand why.

"We hunted all over for a place like this part of Maine," says Elizabeth Gough, a native who, with her husband, runs the Boathouse Gallery in Winter Harbor, "and finally we just came home."