Thousand Islands

State: New York. Type: archipelago of 1,864 islands in the Saint Lawrence River straddling the U.S.-Canada border, spanning Jefferson and St. Lawrence counties in New York and Ontario's Frontenac and Leeds & Grenville counties. Anchor towns on the New York side: Alexandria Bay and Clayton. Home to Boldt Castle (on Heart Island) and Singer Castle (on Dark Island), plus the Antique Boat Museum in Clayton. Boldt Castle is open seasonally, roughly Mother's Day weekend in May through Columbus Day in October.

The Thousand Islands are a sprawling archipelago of 1,864 islands scattered across roughly 50 miles of the Saint Lawrence River between Kingston, Ontario, and the New York shoreline, straddling the U.S.-Canada border. On the New York side, the towns of Alexandria Bay and Clayton serve as the main gateways, connected to Ontario via the Thousand Islands Bridge across Wellesley Island. The region's signature attractions are its two dramatic castles: Boldt Castle on Heart Island, a lavish, unfinished Gilded Age mansion later restored according to its original plans, and Singer Castle on Dark Island, known for secret passageways and hidden rooms. Clayton's Antique Boat Museum preserves the area's boating heritage, and the islands also draw freshwater shipwreck divers and boaters exploring the numerous state parks scattered across the archipelago, including Wellesley Island State Park and the islands protected within Thousand Islands National Park on the Canadian side.

The Thousand Islands stretch about 50 miles along the Saint Lawrence River, straddling the New York-Ontario border. On the New York side they fall within Jefferson and St. Lawrence counties, with Alexandria Bay and Clayton as the principal access towns; the region connects to Ontario via the Thousand Islands Bridge over Wellesley Island.

The Thousand Islands region has a four-season climate typical of northern New York, with cold, snowy winters and warm summers moderated somewhat by the large body of water; boating and castle-touring season runs primarily from late spring through early fall.

Late spring through early fall (roughly Mother's Day weekend in May through Columbus Day in October) is the primary visitor season, since Boldt Castle and most boat tours operate only during this window; summer offers the warmest weather for boating but the largest crowds, while May, June, September, and October offer a quieter visit within the same operating season.

The Thousand Islands' modern tourism identity took shape in the Gilded Age, when wealthy industrialists built elaborate summer retreats on the river's islands, including the two castles that remain the region's best-known landmarks today. Boldt Castle on Heart Island was left unfinished for more than 75 years after its owner's wife died during construction, before being restored according to the original plans. Singer Castle on Dark Island, known as "The Towers," was built with secret passageways and a hidden wine cellar. The region's name is also the purported origin of Thousand Island salad dressing, though the exact story involves competing local claims rather than settled documentation.

Tour Boldt Castle on Heart Island or Singer Castle on Dark Island, explore the Antique Boat Museum in Clayton, or take a boat tour weaving through the islands, many of which are privately owned summer homes. Freshwater shipwreck diving is popular in the surrounding river waters, and state parks such as Wellesley Island State Park offer hiking, camping, and additional water access.

Boldt Castle on Heart Island; Singer Castle on Dark Island; the Antique Boat Museum in Clayton; Wellesley Island State Park; and Thousand Islands National Park, which protects 21 islands on the Canadian side of the border, are the region's principal attractions.

Alexandria Bay and Clayton, the main New York gateway towns, are reached by car via I-81, which crosses the Thousand Islands Bridge into Ontario. Boldt Castle itself is accessible only by boat, via tour operators or private boat from Alexandria Bay; specific ferry/tour schedules should be checked with the operator.

Boldt Castle operates from 10:30 a.m. to 5:30 p.m., per its official site, with the admissions booth closing one hour before the castle itself; hours extend to 7:30 p.m. on Independence Day weekend. The castle is open seasonally, from Mother's Day weekend in May through Columbus Day in October, and is closed the rest of the year.

Boldt Castle admission, per its official site, is $8.50 for adults (13+), $6.00 for children (5-12), and free for children 4 and under; tickets are valid for two years from purchase. This fee does not include the separate boat transportation to Heart Island, which must be arranged independently.

A half day is typically enough for a Boldt Castle tour combined with time in Alexandria Bay; a full day allows for an additional stop at the Antique Boat Museum in Clayton or a longer boat tour through the islands.

Alexandria Bay and Clayton offer a range of lodging from lakeside motels and inns to larger hotels, reflecting their roles as the main tourist gateways to the islands; camping and cabin options are also available within Wellesley Island State Park.

Alexandria Bay and Clayton both have waterfront dining scenes geared toward visitors, with casual and sit-down restaurants clustered along the riverfront in each town; seafood and regional American fare are common given the area's boating and tourism economy.

Clayton's Antique Boat Museum, Wellesley Island State Park, and Singer Castle on Dark Island are all easily paired with a Boldt Castle visit. Across the border, Kingston, Ontario, and Thousand Islands National Park extend the region's attractions into Canada for visitors able to cross.

Interstate 81 connects the region to the rest of New York and crosses the Thousand Islands Bridge into Ontario; there is no direct passenger rail or major commercial airport within the immediate archipelago, so most visitors arrive by car, with Syracuse Hancock International Airport being a more distant commercial-airport option for fly-in visitors.

Because Boldt Castle and many attractions are accessible only by boat, plan tour timing around boat/ferry schedules rather than assuming walk-up access. Standard boating safety practices (life jackets, weather checks) apply for anyone touring the islands independently. For any emergency, dial 911.

A camera for castle and river views, comfortable walking shoes for touring Boldt Castle's grounds, layers for cooler river breezes even in summer, and a valid ticket or boat-tour confirmation since access to the islands is water-based.

Book Boldt Castle boat-tour tickets in advance during peak summer weekends, and confirm the castle's seasonal opening and closing dates (Mother's Day weekend through Columbus Day) before planning a trip, since it is closed the rest of the year. Pairing a Boldt Castle visit with the Antique Boat Museum in Clayton is a popular way to fill a full day in the region.

Dial 911 for any emergency. For Boldt Castle visitor questions, contact information is available via the Thousand Islands Bridge Authority, which operates the site, per the castle's official visitor information.

Boldt Castle (Thousand Islands Bridge Authority) - https://www.boldtcastle.com

This section is being updated and will be available shortly.

This section is being updated and will be available shortly.

This section is being updated and will be available shortly.