The Thousand Islands at a glance
The Thousand Islands are an archipelago at the point where Lake Ontario becomes the St. Lawrence River. The islands lie between New York State and the Canadian province of Ontario. The river towns on the American side, such as Alexandria Bay, Clayton and Cape Vincent, are where most boat trips start. Clayton is about 20 miles (32 km) north-west of Watertown.
Watertown itself sits inland on the Black River. It makes a practical base for a trip to the islands, and the castles, the bridge and the river towns are all day-trip distance. If you want to get on the water, start with our Thousand Islands boat tours.
How many islands are there?
The figure you will see most often is 1,864 islands. The number depends on what counts as an island. One definition asks for land that stays above water all year, covers more than 1 square foot and carries 2 living trees. Another asks for land above water all year with at least 1 tree. Both arrive at 1,864, but there is no single official counting rule, so treat the number as a regional figure and not a survey result.
The border runs between the islands, so a single island is not split between the two countries. That does not mean you can land on a Canadian island from the American side without papers. Not every island is open to visitors, so most people see them from a boat.
Our pick: a Brockville cruise
A cruise from the Canadian side shows how the islands straddle the border; you cross into Ontario to board.
Hand-picked tours, booked through GetYourGuide. Prices are indicative starting prices in US dollars (as of October 2026). Tap a tour for live availability and the current price in your currency.
Thousand Islands tours and cruises
Boat cruises, castle trips and river day trips, with live prices and availability.
Castles on the islands
Two island castles can be visited by boat in the warm season.
Boldt Castle
Admission is separate from the boat ride. The 2026 season ran from 9 May to 12 October.
Singer Castle
A guided castle tour reached by boat. Visits in 2026 ran until 18 October.
Both castles are seasonal, and neither is a year-round visit. Boldt Castle has announced its next opening for 8 May 2027. Plan a castle day between May and October and check the current dates before you book.
Thousand Islands Bridge: tolls and walking
The Thousand Islands Bridge links New York and Ontario and is the usual way to reach Kingston by car. The toll table below has applied since 1 January 2026. The bridge accepts E-ZPass, cash and common credit cards.
| Vehicle | Toll in USD | Toll in CAD |
|---|---|---|
| Car, pickup or motorcycle (2 axles) | $4 | CAD 5.50 |
| Motorhome (2 axles) | $7.50 | CAD 10.50 |
| Car with a single-axle trailer | $6.50 | CAD 9 |
For most visitors in a standard car, the toll is $4 or CAD 5.50, and the other rows apply only if you tow a trailer or drive a motorhome.
Pedestrians use the walkways on the west side, in daylight only, and park at the American Welcome Center. The walkways are seasonal. They close at the end of October and are announced to reopen in spring 2027. Cyclists push their bikes along the walkways and do not ride on the roadways or on I-81. The maximum bike width including accessories is 25 inches (63.5 cm), and special transport needs to be arranged with the bridge authority beforehand. Crossing into Canada by car, bus or boat from the US needs a valid passport. Our Kingston day trip guide has the entry details.
River towns and parks
Where to base a day on the St. Lawrence River.
The St. Lawrence River through the seasons
The islands change with the calendar. Boat tours and the castles belong to the warm months. Castle visits end in mid-October, but that does not close the river towns. Wellesley Island State Park stays open all year, while swimming there runs from 29 June to 7 September in 2026. In winter, Lake Ontario can produce narrow lake-effect snow bands, and snowfall can differ a lot from one place to the next. Our Watertown weather guide lists the monthly averages.
Horne's Ferry between Cape Vincent and Wolfe Island is not running in 2026, so there is no ferry shortcut across the river. To reach Kingston, use the bridge.
Thousand Islands: frequently asked questions
How many islands are in the Thousand Islands?
The commonly quoted number is 1,864. Different definitions of an island exist, so the figure is a regional one, not an official count.
Are the Thousand Islands in the US or Canada?
Both. The archipelago lies between New York State and Ontario, and the border runs between the islands.
How much is the Thousand Islands Bridge toll?
For a car, pickup or motorcycle with 2 axles the toll is $4 or CAD 5.50. A motorhome with 2 axles pays $7.50 or CAD 10.50, and a car with a single-axle trailer pays $6.50 or CAD 9. The table has applied since 1 January 2026.
Can I visit the castles in winter?
No. Boldt Castle and Singer Castle are seasonal. Boldt Castle closed for 2026 on 12 October and has announced 8 May 2027 as its next opening. Singer Castle visits ran until 18 October in 2026.
Can I walk across the Thousand Islands Bridge?
Yes, on the walkways, in daylight and in season. They close at the end of October and are announced to reopen in spring 2027. Bikes are pushed along the walkways, not ridden.
Is this the official Thousand Islands website?
No. It is an independent guide with no connection to the bridge authority, the castles, the boat companies or any public body. Check current hours and prices with each operator before you travel.