Seventeenth-century French explorers gave the beautiful Thousand Islands region of the St. Lawrence River its name, but they miscounted rather badly. Actually, there are about 1,870 islands -- a wonderfully impressive array floating in a short sweep of the river like a vast flock of geese busily feeding in the cool waters swirling around them.

These are the very islands -- it may never have occurred to you to ask -- that gave the creamy, pickle-filled "Thousand Islands" salad dressing its name. It was created, so the story goes, especially for George Boldt, once the owner of New York's Waldorf Astoria Hotel. Like many millionaires at the turn of the century, he kept a summer home on the river. Eventually, he built a six-story European-style castle that is now both a tourist landmark and the subject of a bittersweet love tale.

An enduring summer resort, the Thousand Islands region has not really changed so very much from its Victorian heyday. The graceful charm of those quiet, relaxing days remains, when vacationers came for the summer to stay on their island estates or in the villages along both sides of the St. Lawrence shore. Many of the old island homes are still standing in good repair, and the villages (they still are villages) have aged well. The style is definitely small-town comfortable.

*Not surprisingly, the scenic spectacle of these clustered islands draws large crowds of summer sightseers. The best way to see the islands quickly is aboard one of the large tour boats that depart frequently from almost every river community on two- to five-hour cruises on both sides of the international boundary. They all sail past "Millionaire's Row," a notable collection of large island homes outside the resort town of Alexandria Bay. Afterwards, you can spend a night or two in a motel or small lodge resort, relishing in the river views and the pine-sweet air.

But to enjoy the region the way George Boldt and his wealthy friends did, you should go for a week or more. A number of the island homes -- at least the smaller ones -- are rented out on a weekly basis, which gives you the rare chance of being master or mistress of your own private island. By day, fishing, swimming and boating are just steps from the door. At night, the starry sky -- undimmed by lights -- puts on a dazzling show. You must, of course, rent a motorboat to get to your domain.

*An alternative to this lordly life is to rent a houseboat, humbler admittedly, but you can chug slowly out to any of the island parks, tie up in a cove and fish and swim from the deck. The stars are no less bright, and you have the option of moving from island to island. These large craft are a bit daunting to maneuver, but the rental agent gives you an hour's lesson -- or more if you need it.

The islands -- a fortuitous gift of ancient Ice Age forces that shaped the Great Lakes -- are clustered into the first 50 miles or so of the wide St. Lawrence as it spills from Lake Ontario on its 750-mile journey northeastward to the Atlantic Ocean. This is a river that begins not as a trickle but at full flow, at this point 15 miles wide. On the southern shore is New York state; on the northern shore, the Canadian province of Ontario. So numerous are the islands, and so close to one another, that you are tempted to hop across the river from one to the other.

Instead, the two nations are linked here by the five-span, seven-mile Thousand Islands Bridge leap-frogging the St. Lawrence Seaway, as well as a seasonal pair of auto ferries (frequent service) and hundreds of privately owned or rented power boats flitting like crazed mosquitos back and forth between the islands and both sides of the mainland. Often they must dodge huge cargo ships sailing the seaway to or from the port cities of the Great Lakes to the west.

The islands, the majority of them privately owned, come in a variety of sizes. Wellesley Island, one of the largest, supports several farms, along with a resort village of Victorian-era cottages, a new condo complex and a couple of large New York state parks. Other islands are only big enough for one cottage and a small lawn and garden -- about the size of a homesite in a typical suburban development. On the St. Lawrence, however, the neighbors come visiting only by boat.

And some islands really are only islets, no more than a pile of barren rocks jutting above the water. On one or two of these miniatures, a jokester has raised a solitary birdhouse atop a tall pole -- the only tourist lodging the minimal acreage permits.

Many of the islands are thickly forested, and the views across the rippling flow of the St. Lawrence seem an almost unspoiled expanse of lush green. In places, rocky cliffs rise high above the passing boats, and countless coves invite exploring. A delight to the eye, the islands -- some separated only by narrow, twisting channels -- can prove a maze to inexperienced navigators. It is advisable to go boating with someone who knows the river, or at least take along good charts. Hidden shoals are a danger, too.

All or part of 21 islands -- and many more rocky islets -- form Canada's St. Lawrence Islands National Park, where boaters can tie up for a hike, a picnic or overnight camping. (The park's islands are reached only by boat.) New York's Wellesley Island parks and a half-dozen other state parks that line the mainland shore provide the same pleasures, but these you can get to by car. A span of the Thousand Islands Bridge touches down on Wellesley.

The Thousand Islands region has a longstanding reputation for some of the best bass fishing in the United States (and Canada, if you cross to the other shore). Among the other big summer catches are northern pike and perch. Fall is the season for muskellunge, the big "muskies."

Most of the villages have marinas, where you can rent a boat or charter one with a guide for about $200 a day for one to four people. Fishing is almost as good, and a lot less expensive, from any village or park pier. Worms for bait, almost your only cost, are selling 25 for $1.50 this summer.

A local tradition -- a little something extra for the summer visitors -- is the shore dinner. As the sun sets, the captain of a charter ties up at one of the park beaches and prepares a meal of the day's catch.

All this adds up to a quiet, old-fashioned summer in a relaxed, old-fashioned resort. You may even discover the refreshing pleasure of afternoon naps.

So peaceful now, the Thousand Islands region for many years in America's early history was the scene of much conflict.

The French were the first Europeans to arrive in the area in the mid-1600s, in pursuit of the fur trade with the Indians, while the English settled the American colonies to the south. Eventually the two colonial powers, in conflict at home and in the New World, fought what was known on this side of the Atlantic as the French and Indian War, from 1754 to 1763. As the boundary between French and English interests, the St. Lawrence was a major battlefront.

The British won Canada as their prize, but peace was short-lived. In 1776, the American Colonies declared their independence, and the St. Lawrence became a front line again, this time between England and the new United States. Many colonists, unwilling to join the Revolution, fled north across the river to settle the Canadian shore of the Thousand Islands.

When the War of 1812 erupted between the United States and Great Britain, the region saw renewed fighting, including naval battles on the Great Lakes. The Americans tried unsuccessfully to seize Canada and make it a part of the new nation. At Sackets Harbor, a quiet village just south of the St. Lawrence on Lake Ontario, the United States built a large fort that twice came under attack.

The original site of the fort and several buildings have been preserved as the Sackets Harbor Battlefield State Historic Site. In the summer, guides lead tours of the Commandant's House, and the view of Lake Ontario from the tree-shaded grounds is excellent.

Soon after the war, the British, anticipating further trouble, built Fort Henry across the St. Lawrence at Kingston, now the largest community in the Thousand Islands region. This huge stone fort, fully restored, is open to visitors also. In this day of Canadian-American accord, it seems proper to tour both to get the full story of earlier discord.

Interest in the Thousand Islands as a vacation spot grew after the Civil War among city dwellers seeking cool summer retreats. Inns popped up along the St. Lawrence, and the wealthy who came to visit often decided to buy an island to build a home. One early resident was George Pullman, inventor of the Pullman railroad car. He put the Thousand Islands on the holiday map when, in 1872, he invited President Ulysses S. Grant for a stay. By the end of the century, as many as 20 trains a day arrived in the summer, carrying vacationers to palatial hotels or island homes, according to Don Ross, author of a very informative guide, "St. Lawrence Islands National Park."

George Boldt was one vacationer who became a local legend. He had arrived in the United States from Prussia in 1864, rising from bellhop to owner of the Waldorf Astoria and other hotels. In 1894, he and his wife Louise bought Heart Island, just offshore from the town of Alexandria Bay, N.Y., and they began building what has become known as Boldt Castle, a massive and ornate structure of granite and concrete. As fantastic as Sleeping Beauty's castle, it was designed with soaring towers and more than 150 rooms.

More than $2 million had been spent to complete the exterior when Louise Boldt died suddenly. With her loss, Boldt no longer showed any interest in his castle, discharging the 300 artisans and laborers still working on the interior. It is said he never again entered it. It was soon sold and opened almost immediately to visitors, but for many decades it was allowed to deteriorate. In 1977, the Thousand Islands Bridge Authority acquired the castle and has undertaken a massive and ongoing restoration. All of the island tour boats stop at Heart Island, and you can roam the island and the castle. Most of the rooms are empty -- the home was never furnished -- but that doesn't diminish the spectacle of the place.

The project was flamboyant, even for so conspicuously consuming a period as the early 1900s; and you suspect Boldt, of humble birth, of perhaps wanting to reside in the grand palace he could never have aspired to in his Prussian homeland. But that is not what they tell you on Heart Island. There, the castle is "the testimony of the unsurpassed love of a man for his wife." Well, it is a nicer story.

The region's age of elegance -- when it was known as a playground for the rich -- has long since passed, the result of the Depression, World War II and air travel carrying the jet set elsewhere. Now camping families and dedicated fishermen fill New York's riverside parks. And in place of the palatial old hotels, now there are modern motels and motel-like resorts, such as Alexandria Bay's Edgewood Resort and the beautifully situated Pine Tree Point Resort nearby.

The rich are still around, though not so obviously as before. But more importantly, the river and its islands remain as lovely as before.

To get to know the Thousand Islands, first take a boat tour from one of the river towns, such as Clayton and Alexandria Bay on the U.S. side or Gananoque on the Canadian. You see the islands and their homes close up, and you can tour Boldt Castle. To explore further, plan a day-long circle drive that takes you along both shores of the St. Lawrence to its parks and towns.

The trip begins on the U.S. end of the Thousand Islands Bridge, a few minutes' drive west of Alexandria Bay. The ride across the bridge's five high spans ($2 fee) gives you a fine view of the islands from overhead. If you want a lingering look, park the car at the far end of a span and walk or cycle back.

When the first span deposits you on Wellesley Island, detour left to the resort community of Thousand Island Park for a look at its delightful gingerbread houses and their long porches filled with wicker furniture. You can buy an ice cream cone at a corner shop, stroll for a bit beneath the tall trees shading the street and imagine you have found your way back into the past century.

Nearby is New York's Wellesley Island State Park, where you can swim at a sandy cove, picnic, fish or spend the night in a campground. Swimming becomes tolerable in these northern waters about the Fourth of July. Some people plunge in earlier, but usually they are over-eager tourists who can't wait for the water to warm.

After clearing immigration on the Canadian end of the bridge, turn left on the Thousand Islands Parkway heading to the resort town of Gananoque. The short drive offers a number of nice views of the river along the way. Continuing west is Kingston, a cheery-looking modern city with a flavor of Old England. Fort Henry is on the outskirts as you enter.

In downtown Kingston, you catch the first of two auto ferries back to the United States. It is a large, publicly owned transport (no charge) that operates year-round to Wolfe Island, about a 25-minute ride. Departures are about once an hour from 6:15 a.m. to 2 a.m. To the left as you cross are the Thousand Islands; to the right is Lake Ontario. Even in summer, the breeze off the lake is cool.

If you get an early start and hasten along on this outing, you will arrive at Wolfe Island in time for a late lunch at the General Wolfe Hotel, an inn and restaurant overlooking the tiny harbor. The menu is sophisticated, but you can sample some regional specialties, including "hot Lancastershire pot," a tasty lamb stew.

Wolfe, the largest of the Thousand Islands, is gently rolling farm country. Lightly populated and with little traffic, it is popular with weekend bicyclists, who take the ferry across from either the United States or Canada for pleasant rides on its winding back roads. The drive across the 15-mile-wide island to the second ferry takes about 20 minutes.

This ferry, a miniature compared to the first, carries about a dozen cars, some of them all but hanging over the edge. It is privately owned, and the fare is $5 for car and one passenger and $1 for each additional passenger. It operates only from about mid-May to mid-October, on an hourly schedule from 8 a.m. to 7 p.m. The ride is about 10 minutes to Cape Vincent, N.Y., and U.S. immigration.

Cape Vincent, a tiny Victorian village, is the home of New York state's Cape Vincent Fisheries Station, which has a small aquarium displaying local fish. If your fish knowledge is minimal, you can learn to discern the difference between a small-mouth and a large-mouth bass, if you happen to get either on a hook.

Heading east again along the St. Lawrence, you pass by a string of New York's state parks -- Burnham Point, Cedar Point and Keewaydin, among them -- each a fine place to stop for a walk along the shore, to fish or wiggle your toes in the water. Burnham Point is said to be popular with fishing enthusiasts.

One last stop, and this is in the resort town of Clayton. If you have not tarried, you still have time for a quick tour of the Thousand Islands Shipyard Museum. The focus is on the oar, sail and power craft that have been popular on the St. Lawrence for more than a century. A restored 1902 cabin cruiser, the Narra Mattah, offers short tours, one more chance to get out on the water.

A nice end to a day's sightseeing is dinner at the Pine Tree Point Resort, just east of Alexandria Bay. The restaurant, sitting on a pine-covered promontory, seems to float out over the river, and the sunsets there are gorgeous. Freighters churn by in the distance, and power boats, as frenzied as ever, dart between the islands.

So agreeable is the scene that you may feel tempted -- in the spirit of the occasion -- to order George Boldt's famous Thousand Islands dressing. Don't be foolish. You will want to return home remembering the best of the Thousand Islands, and the region's most famous food, no matter what its origins or where it is served, doesn't qualify.