The Thousand Islands constitute an archipelago of 1,864 islands that straddles the Canada-U.S. border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario. They stretch for about 50 miles (80 km) downstream from Kingston, Ontario. The Canadian islands are in the province of Ontario, the U.S. islands in the state of New York.
The 1,864 islands range in size from over 40 square miles (100 km2) to smaller islands occupied by a single residence, or uninhabited outcroppings of rocks that are only home to migratory waterfowl. To count as one of the Thousand Islands these minimum criteria had to be met: 1) Above water level year round; 2) Have an area greater than 1 square foot (0.093 m2); and 3) Support at least one living tree.
Large freighters frequently ply the Saint Lawrence Seaway, but the area has so many shoals and rocks that vessels sometimes hire maritime pilots to help them travel through the hazardous waterway. Under the Canadian span, a vessel just less than 25 feet (7.6 m) offshore can find itself in over 200 feet (61 m) of water. Similarly, rocks and shoals less than two feet (61 cm) underwater can be found in the center of channels 90 feet (27 m) deep.
Because of the great number of rocks and shoals just above or below the water's surface, it is unwise to travel the waters at night, unless one stays in the main channels and has charts, a chart plotter, or knows the area well. The water is so clear in some areas, that a rocky bottom can be observed in 80 feet (24 m) of water. Before the advent of the zebra mussel, visibility of only ten to fifteen feet was usual, slightly decreasing as the years passed. Water clarity improved markedly in the mid-1990s with the arrival of zebra mussels, which feed on algae. The area has several shipwrecks, and although most of them are over 100 feet (30 m) underwater, some are a mere 15 feet (4.6 m) down and can be seen from the surface.
Around twenty of these islands form the Thousand Islands National Park, the oldest of Canada's national parks east of the Rockies. The park hosts campgrounds, inland walking trails, annual family events, as well as a national heritage building. 
The Thousand Islands-Frontenac Arch region was designated a World Biosphere Reserve by UNESCO in 2002. The U.S. islands include numerous New York state parks, including Wellesley Island State Park, and Robert Moses State Park - Thousand Islands located on an island in the St. Lawrence.
The Thousand Islands Bridge connects New York State and Ontario by traversing Wellesley Island at the northernmost point of Interstate 81 in Jefferson County and meets Highway 137, which leads to Highway 401. The Thousand Islands Parkway provides a scenic view of many of the islands.
The largest island in the group, Wolfe Island, is located entirely in Ontario. Adjacent to Wolfe but part of New York is Carleton Island, the site of a ruined fort, Fort Haldimand, built in 1779 by the British during the American Revolutionary War. The island was captured by three American soldiers during the War of 1812 and remains part of the United States today.
The Thousand Islands is a corridor for nature lovers, and both Ontario and New York have government-regulated parks along the waterfront. The waterfront is served by New York State Route 37 and by the Thousand Islands Parkway in Ontario. Ontario also has the Waterfront Trail alongside the Parkway for cyclists who wish to see the area in an alternative way.
The Thousand Islands gave their name to the popular Thousand Island dressing around the turn of the 20th century when Sophie LaLonde, of Clayton, New York who served the dressing at dinner for guests of her husband, a popular fishing guide, gave the recipe to Clayton hotel owner Ella Bertrand and New York City stage actress May Irwin. Irwin shared it with hotel magnate George C. Boldt.
In the late 19th and early 20th centuries, many distinguished visitors made the region widely known as a summer resort. Several grand hotels provided luxurious accommodations while steamboats offered extensive tours among the islands. Wealthy and middle-class summer residents built summer homes. Some masonry "castles" remain as international landmarks. The most famous extant examples are "The Towers" on Dark Island, now called Singer Castle, and the long-neglected Boldt Castle on Heart Island, much of which has been completed over the recent decades in accord with Mr. Boldt's original plans – hitherto, it had been left unfinished for over 75 years upon the untimely death of his wife. The original plans were updated to incorporate numerous current technological conveniences.
During the half century (1874–1912) of the resort's greatest prominence, most wealthy vacationers came from New York City, joined by prominent families from Chicago, Cleveland, Pittsburgh and other cities of the United States and Canada. The region retains a historically important collection of vacation homes from this time. The Thousand Islands have long been a center for recreational boating. Large steam yachts, many designed by Nathanael Herreshoff required distinctive yacht houses. The region was known also for innovative power boating during this period.
Three local yacht clubs hosted the Gold Cup Races of the American Power Boat Association for nine consecutive years. The Antique Boat Museum of Clayton retains one of the world's major collections of recreational freshwater boats.
The region was also a part of the War of 1812 between the British Empire and the United States. Many sites from the war can be found such as Fort Wellington in Prescott, ON and the garrison on Chimney Island, Mallorytown ON along the 1000 Islands region. Museums about the war can be found on both the Canadian and American side of the river.
Popular boating, fishing and vacationing locations
- One of the few beaches in the Thousand Islands, Potter's Beach (conserved by the Thousand Islands Land Trust - see below) on the American Grindstone Island has a fine, shallow sandy bottom with a very gradual slope, provide a perfect location to anchor up and spend a day at the beach either swimming or hiking on the trails that extend around Grindstone Island.
- A popular location for swimming or anchoring out of the wind, the Lake of the Isles is a secluded area cut off from the rest of the St. Lawrence River by Wellesley Island and neighboring Canadian Hill Island. Access is limited through two narrow passages, one around the northeastern end of the island, and the other being the International Rift, which is a small, shallow, winding canal that leads you through to the north side of the island passing right underneath the customs bridge.
- Known for its fishing,especially pike, Eel Bay is a shallow bay just southwest of Wellesley Island. From the air, the bay can resemble the Caribbean with a turquoise-tinted crystal clear water and sandy bottoms.
- The Thousand Islands Land Trust (TILT) conserves over 8,200 acres of land in the Thousand Islands region. This land includes many creeks, nature preserves and over 30 miles of trails that are open to the public, year-round, free of charge. TILT hosts an annual series of programs - TILTreks, TeenTreks, KidsTreks and TILTKids Camp - that give individuals and families the opportunity to "get out on the land!" These outings include field trips to a preserve for a bird walk or a historical tour, recreational activities such as bike rides and kayak paddles, while our other programs consist of discussions and presentations on wildlife or habitat preservation. TILT's community events help further their conservation efforts in the 1000 Islands region. See TILT's website for more information: www.TILandTrust.org
- Boldt Castle, a testament of one man's love of his wife, has been under renovation by its owner, the Thousand Islands Bridge Authority since 1977, and can be visited by boat or tour cruise. This 120-room mansion is located on Heart Island just across the shipping channel from Alexandira Bay. The grounds consist of the main castle, the power house,the play house, and a boat house tucked in across the bay on the inside of the island. Boldt Castle and surrounding grounds are available for touring, and is also available for wedding ceremonies.
- The Antique Boat Museum in Clayton houses exhibits antique wooden boats used or built in the region. The museum also features exhibits on the region's maritime culture and is home to the LaDuchess, George Boldt's luxury houseboat.
- Though not as famous as George Boldt's Castle, Singer Castle on Dark Island is privately renovated and is open to tourists. Frederick Bourne had his castle constructed with secret passageways and hidden wine cellars so that he could spy on his guests while keeping his liquor out of sight during the prohibition era.
- The Thousand Islands is also said to have some of the best fresh water wreak diving in the world. Numerous wreaks lay at the bottom of the seaway including, The America, The Islander, and The Keystorm to name a few. The amount of wreaks appeal to all diving skill levels, whether you are at a beginning level or an advanced diver, you will find something challenging.
Aviation / Airport
Passenger air service to the 1000 Islands region is available in both Ontario and New York. Watertown International Airport (ART) in Watertown, New York has daily service on American Airlines connecting through Chicago O'hare. Norman Rogers Airport (YGK) in Kingston, Ontario offers daily service on Air Canada connecting through Toronto Pearson. Both airports also offer private aviation services.
Other private aviation airports include: Maxson Airfield (FAA LID: 89NY) is a privately owned, private-use airport located two nautical miles (4 km) south of the central business district of Alexandria Bay, a village in Jefferson County, New York, United States. This general aviation airport is situated in the Thousand Islands region. It once had commercial service provided by Mohawk Airlines. At that time, the airport bore the IATA airport code AXB. Maxson is available to the public by Maxson Airfield, LLC.
Brockville-Thousand Islands Regional Tackaberry Airport (IATA: XBR, TC LID: CNL3), also known as Brockville Municipal Airport, is a registered aerodrome located in Elizabethtown-Kitley Township, 4.8 NM (8.9 km; 5.5 mi) northwest of the city of Brockville, Ontario, Canada.
- In the Saint Lawrence River, about 2 miles (3.2 km) north of Alexandria Bay, Deer Island is owned by the secret society of Skull and Bones.
- There is a pair of islands near Rockport called the Zavikon Island. A popular but incorrect tale among the local tourist guides is that the bigger island is in Canada, while the smaller one is in the USA, and the foot bridge between them is the shortest international bridge in the world. The Zavikon Island is located in the Canadian territory and belongs to the Leeds and Grenville municipal unit.
- Longue Vue Island is the only artificial island in the region.
Thousand Island dressing was named for the chain of islands by the actress who popularised the dressing, May Irwin, stating that she thought the chopped vegetables in the dressing looked like the Thousand Islands region.
Thousand Islands near Ivy Lea, Ontario
- >Parks Canada, Parks Canada, retrieved 2013-05-21
- Clarke, Jay (1983-07-17). "Retreat to the river on the St. Lawrence islands". The Philadelphia Inquirer. p. I09. Retrieved 2007-10-03.
- Shortest International Bridge, Twelve Mile Circle, retrieved 2011-10-15
- Chan, Elise D. (2007). Jefferson County. Arcadia Publishing. p. 58. ISBN 978-0-7385-3547-0.
- "The Venice of America". The Hindu Business Line. 2000-03-13. Retrieved 2007-09-09.
- "ONTERM GeoNames Index: Zachary Islands — Zigzag Island". Government of Ontario. Retrieved 2007-10-03.
- "Geographical Name Search Service (search for Zavikon Island)". Canadian Geographical Names Natural Resources Canada. Retrieved 2007-10-03.
- McNeese, Tim (2005). The St. Lawrence River. Infobase Publishing, ISBN 978-0-7910-8245-4
- The little-known origins of popular dressingsThe Union Democrat February 22, 2005
|Wikimedia Commons has media related to Thousand Islands.|
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- Thousand Islands Life
- Abay.com - 1000 Islands Resource & News Site
- St. Lawrence River / 1000 Islands Live Webcam
- Tourism offices
- 1000 Islands International Tourism Council
- Alexandria Bay Chamber of Commerce, NY
- Clayton Chamber of Commerce, NY
- Cape Vincent Chamber of Commerce, NY
- Brockville Tourism, ON
- Front of Yonge Township Office, ON
- Gananoque Chamber of Commerce, ON
- Kingston Tourism, ON