Thousand Islands Travel Guide: Things to Do, Best Time to Visit & Itinerary

The Thousand Islands region is where the Great Lakes end and the mighty St. Lawrence River begins, creating a freshwater paradise of over 1,800 islands. It is a place where Gilded Age millionaires built authentic castles atop granite shoals and where bootleggers once dodged patrol boats in the moonlight. Today, the area blends that fascinating history with a laid-back river culture that invites you to slow down and watch the ships go by.

Driving along the Seaway Trail, you are met with panoramic views of the water, dotted with islands ranging from the size of a single rock to massive landscapes housing entire state parks. Whether you are navigating the channel in a vintage wooden boat or exploring the secret passageways of a gothic mansion, the Thousand Islands offers a unique escape that feels worlds away from the bustle of city life.

A Playground for Millionaires and Nature Lovers

What makes the Thousand Islands truly special is its dual identity. On one hand, you have the “Millionaire’s Row” history of the late 19th and early 20th centuries. Titans of industry from New York City and Chicago built lavish summer homes here, most notably George Boldt, proprietor of the Waldorf-Astoria, whose tragic love story is immortalized in the stone masonry of Boldt Castle. This era left a legacy of grand architecture and a refined boating culture that persists today.

On the other hand, the region is a raw natural wonder. The Frontenac Arch Biosphere, of which the islands are a part, is one of the most biodiverse areas in the country. Anglers come from all over the world for world-class bass, pike, and muskellunge fishing. The water is crystal clear, thanks to the filtering power of zebra mussels, making it incredible for swimming, diving, and kayaking through the “flats” where the water is calm and warm.

The Icons You’ll Want to See

Boldt Castle - Located on Heart Island, this is the crown jewel of the region. Accessible only by tour boat or private watercraft, admission is $12.50 USD for adults. It is a short 10-minute boat ride from Alexandria Bay.

Singer Castle - situated on Dark Island, this castle features secret tunnels and dungeons you can actually explore. It is about 20 miles downriver from Alex Bay; tours usually cost around $45 USD including the boat shuttle.

The Antique Boat Museum - Located in Clayton, roughly 11 miles from Alexandria Bay. Admission is $14 USD. It holds the largest collection of recreational freshwater boats in the world and offers speedboat rides.

Wellesley Island State Park - A massive park accessible via the Thousand Islands Bridge. It features the Minna Anthony Common Nature Center and miles of hiking trails. Vehicle entry fee is roughly $7 USD.

Rock Island Lighthouse - A historic lighthouse located off the shore of Clayton. Accessible by private boat or a tour from Clayton Island Tours. It offers a climbable tower with panoramic views of the seaway.

Planning Your Visit

Getting to the Thousand Islands usually involves driving, as it is a road-trip destination. It is located directly off Interstate 81 at the New York/Canada border. The nearest major airports are Syracuse Hancock International Airport (SYR), about 90 minutes south, or Watertown International Airport (ART), which is smaller and 30 minutes away. Having a car is essential, as public transport between the river communities of Clayton, Alexandria Bay, and Cape Vincent is virtually non-existent.

When packing, remember that life on the river is casual but weather-dependent. Even in July, the breeze off the water can be chilly at night, so bring a light jacket or sweatshirt. If you plan to cross the International Bridge or take a boat tour that lands in Canada, a valid passport or enhanced driver’s license is mandatory. Don’t forget your swimsuit and comfortable walking shoes for the castle grounds.

The Thousand Islands is a seasonal destination that transforms completely throughout the year. While summer offers the full experience with all attractions open, the “River Rats”, as locals are affectionately known, will tell you that September is the hidden gem. The water is still warm, the air is crisp, and the sunsets over the St. Lawrence are at their most vibrant, making it the perfect time to discover this upstate New York treasure.