Some places look like their postcards. The Thousand Islands look better — roughly 1,864 islands strung along fifty miles of the St. Lawrence River, where New York meets Ontario and the river starts its long run to the Atlantic. If you’re new to the North Country, the geography can be confusing: three river towns, two castles, a shipping channel full of freighters, and a border running right down the middle of the water. This is the lay of the land from someone who grew up with it — which town to use as your base, how to actually get out on the water, and what the famous sights are really like, so your first trip up the river is the one people keep coming back for.
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What Are the Thousand Islands, Exactly?
The Thousand Islands are not one place — they’re a region. Starting where the St. Lawrence River flows out of Lake Ontario and running northeast for about fifty miles toward the Atlantic, the river breaks into roughly 1,864 islands (the official count, and it includes everything from one-tree rocks to full state parks). The international border between the United States and Canada runs right down the middle of the river, which is why you’ll see both countries’ flags and both countries’ boats out there.
A few things worth knowing before you go:
- Most islands are private. Visitors experience the Thousand Islands from the water — from a tour boat, a kayak, or a rented runabout — not by wandering from island to island. The public exceptions are the state parks and the castle islands.
- The river is a working river. This is the start of the St. Lawrence Seaway, so ocean-going freighters share the channel with pleasure boats. Watching a 700-foot ship thread the narrows from your campsite is one of the great free shows up here.
- The Jefferson County side is the American heart of the region. The three towns below — Cape Vincent, Clayton, and Alexandria Bay — are where nearly every first-timer starts.
The Three River Towns: Cape Vincent, Clayton, and Alexandria Bay
These are the three Jefferson County launch points, each with a distinct character. Pick your base based on what kind of trip you want.
Cape Vincent — The Quiet Gateway at the Top of the River
Cape Vincent sits at the very top of the river, where it meets Lake Ontario. It’s a fishing town first and a tourist town second: charter boats, a working waterfront, and the Tibbetts Point Lighthouse standing watch at the confluence of lake and river. This is the quiet end of the region — fewer crowds, lower-key lodging, and the best access to the Lake Ontario side of things.
It’s also the gateway to Canada by water: the seasonal ferry to Wolfe Island connects onward to Kingston, Ontario. If you’re the type who likes to tack a border crossing onto a trip, Cape Vincent makes it easy. Anglers know this town well — the lake-and-river corner here is serious smallmouth and muskie water.
Best for: fishermen, Canada-bound travelers, and visitors who want the peaceful end of the river.
Clayton — The Classic River Town
Clayton is the most complete river town of the three. It has a real main street, a working harbor, the Antique Boat Museum (one of the best small museums in upstate New York — the collection of classic wooden boats is genuinely remarkable), and the Thousand Islands Museum. Clayton Island Tours runs the local sightseeing cruises, and water taxis can get you out to the islands.
Of the three, Clayton is the best all-around base: families get the museum and the harbor walk, boaters get the launches and services, and everyone gets a town that feels like a town rather than a resort strip.
Best for: families, boaters, and anyone who wants one home base for the whole trip.
Alexandria Bay — The Tourist Hub
Alexandria Bay — “A-Bay” to locals — is the classic Thousand Islands vacation town: boardwalk, ice cream stands, mini golf, and the docks where Uncle Sam Boat Tours runs its famous two-nation sightseeing cruises past Boldt Castle and the castles of the Canadian side. The Boldt Castle ferries leave from here too, and in July and August the bay is the busiest, brightest spot on the river.
It’s the most built-up of the three and the best choice for a first-timer who wants everything within walking distance — tours, restaurants, and the sunset over the bay. Just know that parking gets tight on peak weekends, and July–August lodging books up early.
Best for: first-timers, sightseers, and anyone who wants the full classic A-Bay experience.
Town Comparison: Picking Your Base
| Town | Best For | Vibe | Don’t Miss |
|---|---|---|---|
| Cape Vincent | Anglers, Canada-bound travelers, quiet stays | Working waterfront, laid-back | Wolfe Island ferry, Tibbetts Point Lighthouse |
| Clayton | Families, boaters, all-around base | Classic river town, best main street | Antique Boat Museum, Clayton Island Tours, harbor walk |
| Alexandria Bay | First-timers, sightseers | Lively tourist hub, busiest July–August | Uncle Sam Boat Tours, Boldt Castle ferry |
The Sights Everyone Asks About
The big-name attractions explained simply, so a newcomer knows what’s actually worth the time.
Boldt Castle (Heart Island)
The single most-asked-about sight in the region. George C. Boldt — the millionaire proprietor of the Waldorf-Astoria — built this 120-room Rhineland-style castle on Heart Island as a monument to his wife Louise. When she died suddenly in 1904, construction stopped overnight, and the castle sat abandoned and vandalized for over seventy years. The Thousand Islands Bridge Authority took it over in 1977 and has been restoring it ever since — which is why visiting feels like watching history being rebuilt in real time.
Practical notes: Heart Island is reachable only by water — ferry from Alexandria Bay (Uncle Sam Boat Tours) or Clayton (Clayton Island Tours). Plan on half a day. And here’s the detail every newcomer asks about: you do not need a passport to visit Heart Island, as long as you stay on the island and return directly.
Singer Castle (Dark Island)
Boldt Castle isn’t the only castle. Singer Castle, on Dark Island near Chippewa Bay, is the fortress-style counterpart — a real lived-in castle with secret passageways and a dungeon, built by Singer Sewing Machine president Frederick Bourne. It’s reachable by tour boat and tends to be less crowded than Boldt, with a quirkier, more personal feel.
State Parks on the River
The best way to actually stand on an island, rather than float past one, is the state park system. Wellesley Island State Park is the big one — one of the largest public campgrounds in the region, with a nature center and miles of shoreline. Smaller riverfront parks like Grass Point (near Alexandria Bay) and Kring Point offer swimming, picnicking, and campsites right on the water. These fill up fast on summer weekends, so reserve ahead.
Getting on the Water: Tours, Launches, and Rentals
You have three ways to get out on the river:
- Sightseeing cruises: Uncle Sam Boat Tours (Alexandria Bay) runs the classic narrated tours, including two-nation routes; Clayton Island Tours covers the Clayton end of the river. These are the easiest option for first-timers.
- Your own boat: public launches are scattered along the river and Lake Ontario. See our guide to boat launches with trailer parking on Lake Ontario.
- Kayaks and small-boat rentals: available seasonally in the river towns — a quiet morning paddle through the small islands is one of the best experiences the region offers.
Two cautions for boaters: the Seaway shipping channel carries large commercial traffic, so give freighters a wide berth, and respect the no-wake zones near shore and around the islands — the locals (and the DEC) take them seriously.
When to Visit the Thousand Islands
Summer is the season. Tours, castles, museums, and most restaurants run roughly from Memorial Day through mid-October, with July and August at full tilt. September is the local secret — warm water, thinner crowds, and the start of foliage. Fall brings quiet beauty and the foliage run, but by late October most attractions are closed. Winter is nearly all shut down; the river towns go quiet and the castles wait out the season.
If you’re visiting in the fall, pair the trip with our Northern New York Halloween Events 2026 guide for seasonal things to do around the region.
Practical Tips for First-Timers
- Bring layers. River weather changes fast — a sunny morning in Clayton can turn into a windy afternoon on the water.
- Expect spotty cell coverage once you’re out on the water or on the smaller islands. Download maps before you launch.
- Book ahead for peak season. Castle ferry tickets and July–August lodging sell out on weekends. Don’t assume you can wing it.
- Know the parking situation. Alexandria Bay’s lots fill on peak weekends; Clayton is easier. Arrive early or plan to walk.
- Stationed at Fort Drum? Boldt Castle and the river towns are an easy day trip from post — see our New to Fort Drum? Start Here page for more off-post ideas.
- Driving across the border? The Thousand Islands Bridge links Alexandria Bay to Ontario — check our bridge tolls and border crossing guide for current rates, documentation, and wait times before you go.
Frequently Asked Questions About the Thousand Islands
Do I need a passport to visit the Thousand Islands?
Not for the American side — Cape Vincent, Clayton, Alexandria Bay, and the state parks are all in New York. You don’t need a passport for Boldt Castle’s Heart Island either, as long as you stay on the island and return directly. You do need one if you cross into Canada, whether by the Thousand Islands Bridge or by boat.
How many islands are there?
The official count is about 1,864 — and yes, the region has always played a little loose with the number for marketing purposes. The count includes everything down to tiny rock outcroppings.
Which town should I stay in — Cape Vincent, Clayton, or Alexandria Bay?
Clayton for the best all-around base, Alexandria Bay for the classic tourist experience, Cape Vincent for quiet and fishing. You can’t really go wrong — they’re all within about half an hour of each other.
Can you drive across the Thousand Islands Bridge to Canada?
Yes — but it’s worth knowing the Thousand Islands Bridge is actually two bridges, not one. The first span takes you from the New York mainland to Wellesley Island; a second span continues from Wellesley Island to the Canadian side near Gananoque and Kingston, Ontario. So you’ll cross two bridges before your wheels touch official Canadian land. It’s a toll bridge system, and you’ll go through customs, so bring your passport. The spans hopping island to island are half the experience — worth the drive even if you’re just turning around.
When does everything open and close?
Most attractions, tours, and seasonal restaurants run roughly Memorial Day through mid-October. Always check current hours before making the drive — shoulder-season schedules change year to year.