Monticello

''It is unique among the monuments and shrines of the world, in that it is wholly the work of the man it is supposed to commemorate. He picked the site, planned it in its successive forms, directed the construction. The bricks were made on his mountain, the timber came from his woods. He selected the furnishings and designed the draperies.''

And who was he but Thomas Jefferson? The monument to his memory? Monticello, in Charlottesville, Va.

An excursion to Monticello and to Jefferson's architectural masterpiece, the ''academical village'' at the University of Virginia, is a mere 2 1/2 to 3 hours from the nation's capital, and yet there is a sense of going ''down into an altogether different land'' - a land of rolling hills, clinging mist, and a heavy presence of earth and wood.

Two hundred years ago this journey would have been no pleasure jaunt but a trying task, a difficult expedition to the edge of the wilderness.

I traveled to Charlottesville to do much more than amble among the ghosts of the early years of the Republic. Exhumed bottles, mastodon bones, French clocks, and Argand - whale-oil - lamps, all with Jefferson associations, do indeed tell a tale, but Monticello and the University of Virginia are symbols of a masterly mind. Some say Jefferson was one of perhaps half a dozen of the type in the history of mankind.

My first aim was to visit the man who, in our time, must know Thomas Jefferson best: Dumas Malone, the scholar whose ''long journey with Mr. Jefferson'' has at last paused with the publication in 1981 of the sixth and final volume of his monumental ''Jefferson and His Time.''

Mr. Malone, at 90 still conveying a sense of intellectual and physical vigor, has studied Thomas Jefferson for more than 40 years, and he sums up his subject with zestful affection.

''People often ask, 'How could you devote yourself so long to one person?' Well, they have a false impression,'' Mr. Malone says. ''I consider that I have made a journey through history in the company of Mr. Jefferson. Think of going through the period of the French Revolution, the American Revolution, the Napoleonic Wars, and the beginning of the Republic in the presence of the man who was in touch with all of it. Thomas Jefferson lived through one of the most exciting periods in human history. Anybody could spend his life trying to understand those years.''

The building of Monticello, like the writing of Malone's biography, was the work of 40 years. It was begun in 1769 or 1770 - when Jefferson was 35 - on land willed to Jefferson by his father, Peter. Not until Jefferson retired from the presidency of the United States in 1809 would he discontinue the building and tearing down he was so fond of.

For us today, the finished house is an illumination of Jefferson's character, a demonstration of his love of books, of privacy, of light, air, and sunshine. Jefferson's admiration of the Roman classical orders - displayed on cornice and frieze - his originality and multitude of interests, are displayed at every turn.

It is not a woman's house, Mr. Malone informs us. Mrs. Jefferson - Martha Wayles Skelton - lived but a few months beyond the completion of the ''first'' Monticello. Jefferson's daughters, says Mr. Malone, ''would not have presumed to tell their father how to design a house.''

Monticello is astride a mountaintop, in Jefferson's day an original choice of site, squarely against the plantation tradition of locating on the banks of a river. Jefferson's home, west of the Rivanna River and facing the Blue Ridge Mountains, looked out on an open vista that matched Jefferson's spiritual and intellectual vision.

Monticello's exposed position would challenge Jefferson. Thin, red topsoil, brutal winds, and dry summer heat would keep Jefferson busy devising clever ways of turning obstacles into advantages.

There is a mystical atmosphere about Monticello, this elegant, domed structure with octagonal bays, columned porticoes, and hidden dependencies, as it emerges at the top of the ''roundabouts'' Jefferson included in his Monticello road plan.

From the time Jefferson was a student at William and Mary College in Williamsburg, he was intrigued with the study of architecture. According to Frederick D. Nichols, University of Virginia's Langhorne Professor of Architecture and a Jefferson specialist, the first version of Monticello was meant to be little more than a ''bachelor's pad.'' Nonetheless, from the beginning Jefferson drew upon the works of eminent European architects, in particular the ''Four Books of Architecture'' by the 16th-century Italian genius Andrea Palladio, whose concepts have influenced North American public and domestic architecture to this day.

Fascinated with octagonal rooms, an obsession climaxed by his design for Poplar Forest, his country retreat south of Monticello in Bedford County, Jefferson first drew plans for a central pavilion flanked by a bedroom and dining room with octagonal bow ends. The second floor was to house a library and two additional bedrooms. The facade would be distinguished by Palladian-style double porticoes, one on top of the other, though apparently construction never got far.

The ever-changing, ever-learning Jefferson was to have his architectural notions turned topsy-turvy by his years in Europe as the United States foreign minister to France in 1784-89. Believing as he did that fine paintings and sculpture were beyond the means of a new republic, Jefferson took advantage of his European assignment to absorb English and continental notions of domestic and public buildings as well as of gardens.

The Monticello we know today is the eclectic product of this most catholic of men. ''These days,'' complains Dumas Malone, ''architects think you've got to be original. That didn't matter the slightest to Mr. Jefferson. He was sitting on a mountaintop on the edge of a wilderness. He wanted to build a house and got help any way he could.''

Entranced by the homes of the French nobility - noblemen of the court of Louis XVI - Jefferson kept them in mind while doubling the size of Monticello, removing its top story, and adding a dome, and altering the facade to give the impression of its being a one-story house.

Monticello was now of neoclassic design, marked by both elegance and by devices for service and movement throughout the house, which emphasized the privacy and comfort he had observed in Paris town houses.

Although the second and third floors of Monticello, with the splendid Dome Room and odd little bedrooms, are not open to the public, the guided tours through the first floor quarters well impart the flavor of this remarkable home and of the man who built it.

But there is much more to Monticello than the house itself and its dependencies, all now protected and maintained by the Thomas Jefferson Memorial Foundation, which took charge in 1923.

Amiably neglected throughout the previous century, Monticello is now probably in the best condition of its entire existence. Its sagging floors are reinforced by steel beams, its exterior walls repaired and waterproofed, its interior and furnishings protected by modern heating and air-conditioning systems.

These days, much of the most interesting work afoot at Monticello involves the restoration of Jefferson's vegetable gardens and orchards, a five-part plan involving a team of a horticulturist, geologist, landscape architect, archaeologist, and architectural historian. A 1,000-foot retaining wall on the garden's southern edge has already been reconstructed. In the works, but not yet completed are a garden pavilion - 12 feet, 6 inches square with arches topped by a pyramidal roof and a Chinese-style railing - and the staked fence Jefferson designed to keep wild animals away from the gardens.

Gardening, for Jefferson, was no matter of simple survival, and his thoughts and efforts are remarkably well documented in his Garden Book and Garden Calendar. Jefferson's 1812 garden, the model for present restoration efforts, was laid out in a series of squares bordered by grass walks, the vegetables themselves planted according to whether they were needed for roots, leaves, or fruits. Now 670 feet long, the garden will shortly be extended to a full 1,000 feet with the removal of a visitors' parking lot.

From 1769 to his death in 1826, Jefferson supervised and documented the planting of as many as 150 fruit varieties and 250 vegetable species. In a busy correspondence with the Comtesse de Noailles de Tesse, aunt of his friend the Marquis de Lafayette, Jefferson exchanged plants and seeds over a period of many years. He imported English cherries, French pears, grapes from Italy, and vegetables brought back from the American West by the Lewis and Clarke expedition.

It's an impossible task to find all the many species planted by Thomas Jefferson. Many died out long ago, while others are identified in Jefferson's records by such obscure nomenclature as to elude the most persistent investigator. According to Peter Hatch, superintendent of grounds at Monticello and head of the garden and orchard project, at most ''45 percent of Jefferson's fruit varieties and 15 percent of his vegetable varieties are retrievable.'' When possible, Mr. Hatch will make substitutions that closely approximate what Jefferson would have planted.

When in Charlottesville, see both Monticello and the ''academical village'' of the University of Virginia with its stunning Rotunda (see accompanying story). Then, curl up in front of a toasty fire with a volume of Dumas Malone's comprehensive biography - and begin your own ''long journey with Mr. Jefferson.'' Practical details:

Monticello is included in an eight-day American Heritage tour, along with other cities and sites from the Colonial period and the Revolutionary and Civil Wars. The tour begins in New York, goes south to Virginia, then returns via the Natural Bridge, Skyline Drive, and the Pennsylvania Dutch countryside. A brochure is available from Cosmos, 69-15 Austin Street, Forest Hills, N.Y. 11375 .

Monticello is open every day except Christmas; its hours are 8:00 a.m. to 5 p.m. between March and October, with slightly shorter hours in the winter. Admission fee is $3 for adults, $1 for children, ages 6-11.

The Guesthouse Reservation Service will put you up in a cottage or private home - some very elegant - for $36 to $72 double, depending on the accommodations. Write P.O. Box 5737, 107 Bollingwood Road, Charlottesville, Va. 22905; or call 804-979-7264 or -8327, Monday-Friday between 1 and 6 p.m.