The first thing you notice about the Thousand Islands is the color of the water. The St. Lawrence River runs a shade of blue-green that seems too vivid for upstate New York, too clear for a waterway that drains the entire Great Lakes system into the Atlantic. Then you notice the islands. They start appearing as your boat pulls away from the Alexandria Bay dock — granite outcroppings topped with a single wind-bent pine, larger islands with Victorian cottages perched right at the waterline, and everywhere the play of light on water that shifts from emerald to cobalt depending on the depth and the angle of the afternoon sun.
I came to the Thousand Islands expecting a minor detour on my way through northern New York. Three days later, I was standing on the stone terrace of a castle built for love and abandoned in grief, watching a container ship from the Great Lakes glide silently between islands, and understanding why the wealthy families of the Gilded Age chose this place above all others to build their summer palaces. The Thousand Islands have that rare quality of being simultaneously grand and intimate — a landscape of castles and shipping channels that somehow also feels like a quiet fishing village where everyone waves from their boats.
The River and Its Islands
The numbers alone are remarkable. There are 1,864 islands in the archipelago, stretching roughly 50 miles along the St. Lawrence River from Cape Vincent at the eastern end of Lake Ontario to Brockville, Ontario. The islands straddle the international border between the United States and Canada, and the invisible line between the two nations runs right through the middle of the river channel. Some islands are just big enough for a single cottage and a dock. Others support entire communities. A few are barely more than exposed rock with a stubborn tree clinging to the cracks.
The definition of a Thousand Island is charmingly specific: it must be above water 365 days a year and support at least one living tree. By that standard, you get 1,864. By a looser definition — anything that pokes above the waterline — you get far more. The precision matters to locals, who take their island count seriously and will correct you if you round down.
The river itself is the star. Fed by all five Great Lakes, the St. Lawrence moves with a purposeful current that keeps the water clean and cold, even in August. Freighters and container ships transit the St. Lawrence Seaway through the main channel, and watching these massive vessels pass silently between tiny cottage islands — close enough that you could theoretically toss a baseball onto their decks — is one of the region’s more surreal sights.
1,864 Islands, One River
The St. Lawrence River scatters nearly two thousand islands across the U.S.-Canada border — granite, pine, and Gilded Age castles rising from water so clear it seems lit from below.
Boldt Castle — A Love Story in Stone
Every visit to the Thousand Islands begins and ends with Boldt Castle, and that is entirely appropriate. The castle is not just the region’s signature attraction — it is the story that defines this place, a narrative of extravagant love, sudden loss, and seven decades of beautiful ruin.
George C. Boldt was a Prussian immigrant who rose to become the proprietor of the Waldorf Astoria Hotel in New York City, the most famous hotel in the world at the turn of the twentieth century. In 1900, he began construction of a full-size Rhineland castle on Heart Island — a six-story, 120-room monument to his wife, Louise. Three hundred workers labored on the project. Boldt had the island itself reshaped into the form of a heart. Italian gardens, a power house designed to look like a medieval tower, and an elaborate yacht house with its own living quarters were all part of the plan.
Then, in January 1904, Louise Boldt died suddenly. George sent a telegram to Heart Island with three words: “Stop all construction.” He never returned. The castle, nearly complete but still unfinished, was left open to the elements for 73 years. Rain fell through the roofless towers. Vandals took what they could carry. The grand staircase rotted. Heart Island became the most romantic ruin in America.
In 1977, the Thousand Islands Bridge Authority acquired the castle and began a decades-long restoration effort funded entirely by tourism revenue. Today, Boldt Castle is open to visitors from mid-May through mid-October, accessible only by boat from Alexandria Bay. The restoration has been meticulous — the grand ballroom, the circular tower rooms, and the Italian gardens have been brought back to life. But traces of the abandonment remain in the stonework and the empty window frames of sections still under restoration, and those traces are what make the castle more than just another historic house. It is a place where you feel the weight of a love story that ended too soon.
Practical note: Uncle Sam Boat Tours runs regular departures from Alexandria Bay to Heart Island. The ride takes about ten minutes, and you can spend as long as you want exploring the castle before catching a return boat. Admission to the castle is separate from the boat fare. Budget two to three hours for the full experience.
Singer Castle on Dark Island
If Boldt Castle is the romantic tragedy of the Thousand Islands, Singer Castle is the mystery. Located on Dark Island near Chippewa Bay, this medieval-style castle was built in 1905 for Frederick Bourne, president of the Singer Sewing Machine Company. Where Boldt Castle is open and light-filled, Singer Castle is deliberately dark, fortified, and full of hidden passages.
The castle was designed by Ernest Flagg, the same architect who designed the Singer Building in Manhattan (once the tallest building in the world). It features secret passageways behind walls, a dungeon, a two-way fireplace with a hidden observation room behind it, and corridors designed so that the owner could observe guests without being seen. The tours lean into this atmosphere, and the guides are excellent at revealing the castle’s secrets one at a time.
Singer Castle receives far fewer visitors than Boldt Castle, which is part of its appeal. The boat ride from the mainland takes longer, the tour groups are smaller, and the atmosphere is more intimate. If you only have time for one castle, Boldt is the essential choice. But if you have two days on the water, Singer Castle is the more unusual and in some ways more memorable experience.
Alexandria Bay — The Hub of the Islands
Alexandria Bay, known locally as Alex Bay, is the tourist hub of the Thousand Islands. It sits on the American side of the river directly across from the Canadian town of Rockport, and its waterfront is where most visitors base their explorations. Uncle Sam Boat Tours, the primary operator for Boldt Castle excursions and narrated river cruises, departs from the center of town.
The village itself is compact and walkable — a handful of blocks between the river and Route 12 packed with restaurants, gift shops, ice cream parlors, and the kind of waterfront bars where the sunset crowd gathers every evening in summer. It is undeniably touristy in July and August, but the setting is so naturally beautiful that the tourist apparatus feels forgivable.
The best thing about Alex Bay is the access it provides to the water. Within five minutes of any dock in town, you are surrounded by islands. The Two Nation Tour cruises through both American and Canadian waters, passing between private islands with elaborate cottages, under the Thousand Islands Bridge, and past Boldt Castle, Singer Castle, and the miniature castle on one island that was built to hold exactly one person and a barbecue grill. The narrated history of the millionaires who built summer estates on these islands — the Pullmans, the Bournes, the Boldts — is a fascinating window into Gilded Age excess.
Clayton — The Quieter Side
If Alexandria Bay is the tourist hub, Clayton is the cultural heart. This small river town about 12 miles west of Alex Bay has reinvented itself around the Antique Boat Museum, excellent waterfront dining, and an arts community that has brought new energy to its brick-and-limestone downtown.
The Antique Boat Museum is world-class — the largest collection of antique and classic boats in North America, housed in a campus of exhibit buildings on the Clayton waterfront. The collection includes gorgeous mahogany speedboats from the 1920s and 1930s, historic St. Lawrence skiffs, and George Boldt’s own houseboat, the La Duchesse. Even if you have no particular interest in boats, the craftsmanship on display is extraordinary.
Clayton’s restaurant scene punches above its weight. Thousand Islands Winery offers tastings with river views. Lyric Coffee House is the morning gathering spot. The waterfront dining options serve fresh walleye, perch, and pike caught that same day from the river.
Where the Gilded Age Built Its Playground
Millionaires chose these islands for a reason — the river light, the granite shores, and a privacy that only water can provide. Their castles still stand as proof.
Wellesley Island State Park
Wellesley Island State Park occupies the southwestern portion of Wellesley Island, the largest island in the American section of the archipelago. Accessed via the Thousand Islands Bridge, the park is the best base for visitors who want to combine outdoor recreation with island exploration.
The park’s campground offers over 400 sites — tent sites, RV hookups, and cabins — spread across wooded loops that feel remarkably secluded despite the park’s popularity. The Minna Anthony Common Nature Center within the park has six miles of trails through wetlands, forests, and along the river shoreline. The center itself houses exhibits on the region’s ecology and is a good starting point for understanding the natural systems that make the Thousand Islands unique.
Swimming at the park’s sandy beach on the river is a highlight. The water is clean and refreshingly cold even in midsummer. Kayak and canoe rentals are available, and paddling from Wellesley Island into the surrounding maze of smaller islands is one of the best ways to experience the region at a pace that lets you appreciate the quiet — the lap of water against granite, the call of a loon, the occasional splash of a bass breaking the surface.
Fishing the St. Lawrence
The St. Lawrence River through the Thousand Islands is one of the premier freshwater fisheries in the northeastern United States, and serious anglers have been coming here for over a century. The river holds exceptional populations of smallmouth bass, largemouth bass, walleye, northern pike, and muskellunge. The bass fishing, in particular, is nationally ranked — the clear water and rocky structure create ideal smallmouth habitat, and catching 40 to 50 bass in a single day is not unusual with a good guide.
Fishing charters operate out of Alexandria Bay, Clayton, and Cape Vincent. Half-day trips run four to five hours and are enough to get into fish. Full-day charters allow you to explore more water and target multiple species. Most guides provide all tackle, and many are patient teachers who welcome beginners.
The walleye fishing peaks in May and June when fish move into shallower water. Bass fishing is best from late June through September. Pike and muskie are available all season but are most active in fall. Shore fishing from state park docks and public access points is productive for anyone who does not want to hire a charter.
Where to Eat in the Thousand Islands
Riley’s by the River (Alexandria Bay) — Waterfront dining with a massive patio overlooking the river. Fresh fish, steaks, and cocktails while watching boat traffic. The Friday night fish fry ($16) is a local institution. Casual atmosphere, river-town pricing.
Clipper Inn (Clayton) — A regional favorite for over 70 years. The menu leans into steaks, seafood, and comfort food done well. The Clipper Inn burger and the battered walleye are the standards. $15-30 per entree.
Thousand Islands Winery (Alexandria Bay) — Wine tasting with river views and a relaxed patio. Local wines range from dry whites to sweeter fruit blends. Light food menu pairs well with an afternoon on the patio between boat tours.
Bella’s (Clayton) — Italian-American dining in a renovated downtown building. Handmade pasta, wood-fired pizza, and a solid wine list. $18-35 per entree. Reservations recommended in July and August.
Cavallario’s Steak & Seafood House (Watertown) — If you are passing through Watertown on the way in or out, this institution has been serving prime cuts and seafood since the 1950s. Old-school steakhouse atmosphere with prices that feel like a time machine compared to Manhattan.
Where to Stay in the Thousand Islands
Waterfront: Bonnie Castle Resort in Alexandria Bay puts you right on the river with direct access to boat tour docks. Balcony rooms with river views are the way to go — watching freighters and pleasure boats pass at sunset becomes addictive. $160-300/night.
Upscale: 1000 Islands Harbor Hotel in Clayton is the region’s most polished option. Rooftop pool, craft cocktail bar, and a location steps from the Antique Boat Museum and downtown dining. $200-380/night.
Camping: Wellesley Island State Park campground is the best budget option and one of the best camping experiences in New York. Sites range from $20-35/night, and the cabins ($65-120/night) are a good compromise between camping and hotel comfort.
Budget: Numerous motels along Route 12 between Clayton and Alex Bay offer clean, basic rooms for $80-140/night in peak season. The Edgewood Resort in Alex Bay is a reliable mid-budget choice with a pool and river access.
Practical Details
The Thousand Islands tourist season runs from mid-May through mid-October. Most boat tours, castles, and seasonal restaurants close for winter. Peak season is July and August, when accommodation should be booked well in advance, especially for weekends. Late June and early September offer the best balance of warm weather, open attractions, and manageable crowds.
The international border runs through the river. If you want to visit the Canadian side, take a cruise that enters Canadian waters, or cross the Thousand Islands Bridge, you will need a valid passport or enhanced driver’s license. The bridge toll is $3.75 USD.
Cell service is generally reliable in the towns but can be spotty on the water and on smaller islands. Weather can change quickly on the river — bring layers even in summer, as wind off the water drops temperatures noticeably, especially on evening cruises.
- Best Day: Morning boat tour to Boldt Castle from Alexandria Bay (depart early to beat crowds), explore the castle for 90 minutes, return and grab lunch on the waterfront, drive to Clayton for the Antique Boat Museum in the afternoon, dinner at Clipper Inn or Bella's. That covers the essentials in one packed day.
- Bring a Passport: Even if you have no plans to visit Canada, having your passport opens up the Two Nation Tour cruises and the option for a spontaneous trip across the bridge to Gananoque or Brockville on the Ontario side. Without it, you are limited to American-side tours only.
- Thousand Islands Dressing: Order it everywhere. The local versions bear almost no resemblance to the bottled stuff in grocery stores. It was invented here — Sophia LaLonde of Clayton gets the credit — and restaurants throughout the region make their own from scratch. Ask which places make it in-house.
- Sunset Strategy: The best sunset views are from the water. If you cannot get on an evening cruise, the public docks in Clayton and the waterfront park in Cape Vincent both face west across the river for unobstructed sunset views. Alex Bay faces north, so sunsets are less dramatic from town.
- Kayak the Islands: Rent a kayak from Wellesley Island State Park or one of the outfitters in Clayton and paddle into the islands. The experience of weaving between granite islands in your own boat, at your own pace, with no engine noise — just water and rock and pine — is fundamentally different from seeing the same islands from a tour boat. Allow half a day minimum.
- Avoid: The first two weeks of July (around Independence Day) are the most crowded and expensive period. If your schedule allows, the last two weeks of June or the first two weeks of September are significantly better — same warm weather, half the crowds, lower prices, and better fishing.
The Thousand Islands belong to that small category of American places where the landscape is so inherently dramatic that human history could only respond by building something equally dramatic on top of it. The castles, the bridges, the Gilded Age cottages perched on granite ledges — they are all attempts to match the scale of a river that scatters nearly two thousand islands across an international border and then calmly continues on its way to the Atlantic. The river does not care about the castles. It was here before them and will be here long after. But for the visitor standing on the terrace of Boldt Castle, watching the afternoon light turn the St. Lawrence into liquid emerald, the combination of natural grandeur and human ambition creates something that neither could achieve alone. The Thousand Islands are proof that some places simply demand a response, and the response, when it comes, only makes the original landscape more beautiful.