🌤 Weather at Croil Island State Park by season
| Spring | Summer | Fall | Winter |
|---|---|---|---|
| 19–68 °F | 53–81 °F | 27–71 °F | 6–32 °F |
Each range runs from the coldest monthly average low to the warmest monthly average high in that season (1991-2020 climate normals), measured at Massena Intl Airport, 10 mi away, elevation 214 ft. Conditions at the park can differ from the station, especially where elevation differs — check a forecast before you go.
🏆 St. Lawrence Island — Island park on the St. Lawrence River — part of the legendary Thousand Islands region, one of the most scenic waterways in North America
Croil Island State Park is an island in the St. Lawrence River — part of the legendary Thousand Islands region. The Thousand Islands (actually 1,864 islands!) stretch for 50 miles along the US-Canada border where Lake Ontario flows into the St. Lawrence River. The region was a playground for Gilded Age millionaires — George Boldt (Waldorf-Astoria owner) built a 120-room castle on Heart Island for his wife. Thousand Islands salad dressing was invented here! The islands formed when the last glaciers retreated, flooding an ancient river valley and leaving granite hilltops exposed as islands.
Visitor Information
| Detail | Information |
|---|---|
| Location | St. Lawrence River, NY |
| Entry Fee | Free |
| Islands | 1,864 islands — “Thousand” is modest! |
| Fun Fact | Thousand Islands dressing invented HERE! |
About Croil Island
Croil Island State Park in St. Lawrence County provides island recreation in the St. Lawrence River — the great waterway connecting the Great Lakes to the Atlantic Ocean. The Thousand Islands region, where Croil Island sits, contains over 1,800 islands and has been a resort destination since the Gilded Age. Thousand Island salad dressing was invented here in the early 1900s. The island is accessible only by boat.
Things to Do
Boating to the island, camping, fishing for muskellunge, smallmouth bass, and northern pike, kayaking through the Thousand Islands, and exploring one of America’s most scenic river archipelagos.
Insider Tips
St. Lawrence River: Croil Island sits in the St. Lawrence River — the outlet of the Great Lakes and one of the world’s great waterways. Pro tip: The St. Lawrence Seaway (1959) allows ocean-going ships to reach the Great Lakes — 2,340 miles from the Atlantic. Thousand Islands: The region contains 1,864 islands — some barely larger than a dining table.
Best Time to Visit
Summer: Island exploration and fishing. Fall: River foliage. Spring: Musky fishing season. Winter: Ice fishing.
Frequently Asked Questions
How many Thousand Islands are there?
There are exactly 1,864 islands in the Thousand Islands — to qualify, an island must support at least one tree and be above water year-round. They range from tiny rock outcrops to large inhabited islands. The region straddles the US-Canada border — creating a unique international waterway. Thousand Island dressing was reportedly invented here in the early 1900s, named after the region.
Keep exploring: The closest neighbors are Coles Creek State Park (a short drive away) and Higley Flow State Park (within about an hour’s drive).
Wildlife & Nature
Croil Island SP — on the St. Lawrence River — preserves an island accessible by boat. The island’s forest and shoreline provide habitat for bald eagles, osprey, and great blue herons. Common terns nest on the rocks. Smallmouth bass provide excellent fishing around the island. River otters play in the channels.
Nearby Attractions
Waddington — nearby. Ogdensburg — 15 miles west — has the Frederic Remington Art Museum. Massena — 15 miles east — has the St. Lawrence Seaway and Eisenhower Lock. Robert Moses SP — nearby.
🐾 Dogs & Pets at Croil Island State Park
- Pets allowed? statewide rule
- Pets are permitted in most state parks and campgrounds (maximum two pets per site where allowed), but policies vary by park and some parks prohibit pets entirely.
- Leash rule statewide rule
- Leash no longer than 6 ft required, pet under control at all times
- Beaches & swim areas statewide rule
- Pets are not permitted on guarded beaches, boardwalks, pools or spray-grounds
- Cabins & lodging statewide rule
- No uniform statewide rule — pets are prohibited in buildings and most cabins, but some parks designate pet-friendly cabin areas (e.g. Letchworth Cabin Area C); check with the individual park
- Statewide exceptions statewide rule
- Proof of rabies vaccination required upon request; maximum two pets per campsite; some parks (e.g. Wildwood State Park) do not allow pets at all
Are dogs allowed at Croil Island State Park?
Pets are permitted in most state parks and campgrounds (maximum two pets per site where allowed), but policies vary by park and some parks prohibit pets entirely. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via parks.ny.gov. More: New York state parks guide · Dog rules in all 50 states compared
Park Location
Plan your gear for Croil Island State Park
From our editorial guides, matched to this park’s activities:
