Muskellunge · Lake Ontario
Almost all of Lake Ontario's muskie fishing is in the upper St. Lawrence River, from Cape Vincent through the Thousand Islands, plus the eastern end of the lake those same fish roam after spawning. It is one of the few self-sustaining Great Lakes muskellunge populations and a true trophy fishery, but it has declined and is slow fishing even by muskie standards.
Prime time
Late August through November, with October and November the trophy window
Depths
8–18 ft on weed edges and shoal tops in early fall; 20–40 ft along channel drop-offs by late fall
Typical size
38–46 inches
Lake max depth
802 ft
Where
The heart of the river fishery, entirely inside New York. NYSDEC points fall anglers to the Grindstone shorelines, and the New York state record — 69 pounds 15 ounces — came out of the river near Clayton in 1957.
Where Lake Ontario becomes the St. Lawrence. Rose Bay near Cape Vincent is a studied muskellunge spawning and nursery bay, and radio-tagged adults move up into this reach and the eastern lake after spawning.
The only true Lake Ontario muskie water on the U.S. side. Grenadier Island and nearby Fox Creek are listed muskellunge nursery sites, and recovery stocking has included eastern Lake Ontario.
Down-river through the Thousand Islands. Shoals, island points and weedy bays on both sides of the channel. Trolling shoal edges between Cape Vincent and Ogdensburg is the classic NYSDEC-recommended approach.
Lake Ontario's other muskie water, at the opposite end of the lake. NYSDEC lists the lower Niagara among New York's naturally reproducing muskellunge fisheries. Heavy current and serious boat handling.
How
The standard St. Lawrence program, late August through November. Large crankbaits and big spoons along the outside of shoals and the channel drop-offs, 2.5 to 4.0 mph. In October and November, follow NYSDEC's lead around Grindstone and fish deeper with downriggers and planer boards, running baits in 20 to 40 feet.
Late August and September, before the weeds fall. A 9- to 10-inch rubber bait, an 8- to 10-inch tube or a big bucktail over 8 to 16 feet, worked along weed edges and the current-side points of islands. Figure-eight every cast.
October and November around Cape Vincent, Mud Bay and Grenadier Island. These are fish that left the river bays after spawning to feed in the eastern lake. Troll the breaks between shoals and deeper water and expect long gaps between bites.
NYSDEC notes these fish average 12 to 30 pounds with occasional 50-pound fish. Fish an 8- to 9-foot heavy rod, 80 to 100 lb braid and a 100 to 130 lb fluorocarbon leader. Land them fast, keep them in the water, and release them.
Lake Ontario is a trout and salmon lake. Along the New York south shore from the Niagara to Oswego, the open water is deep, cold and built for trolling chinook and lake trout. It is not muskellunge water.
The muskie fishery that carries Lake Ontario’s name lives where the lake drains. At Cape Vincent, the eastern basin narrows into the St. Lawrence River, and the upper river through the Thousand Islands holds one of the few self-sustaining muskellunge populations in North America. Most of the fishing on this page is in that river. Some of it is in the eastern end of the lake. A small part is at the opposite end, in the lower Niagara.
The river fish do not stay in the river. Muskellunge spawn in the shallow, weedy bays of the St. Lawrence in spring. Afterward, a share of the adults swim upstream into the lake. In a radio-tagging study summarized in the St. Lawrence management plan, about half of 47 tagged adults moved up into the Cape Vincent–eastern Lake Ontario region after spawning, some traveling close to 100 kilometers.
The eastern basin also has nursery water of its own. The management plan lists sites at Grenadier Island and Fox Creek near Cape Vincent, and Rose Bay just down-river is one of the best-studied muskellunge nursery bays on the river.
So the U.S. lake water around Cape Vincent, Mud Bay and Grenadier Island is legitimate fall muskie water. It is just thinly populated, and most of the fish in it were born in the river.
The core of the fishery runs from Cape Vincent down through Clayton and Alexandria Bay. NYSDEC’s own guidance is plain: from late summer through fall, troll the edges of shoals between Cape Vincent and Ogdensburg with large spoons and plugs. In October and November, the Grindstone Island shorelines are a favorite, fished deep with downriggers and planer boards.
History sits on this water. The New York state record muskellunge, 69 pounds 15 ounces, came out of the river near Clayton in 1957.
What NYSDEC also says plainly is that it can take more than 30 hours to catch one, and that a guide is a good idea for anyone new to it. Believe them. The river is big, the current is real, and the fish are spread out.
If the muskie are not cooperating, the same Thousand Islands bays and the eastern basin are excellent northern pike water. And if numbers matter more than the river’s mystique, Lake St. Clair is the densest muskellunge fishery in the Great Lakes.
The St. Lawrence fishery has been worked on for a long time. Catches fell through the 1970s, the first management plan followed in 1980, and harvest by anglers dropped sharply over the decades after as catch-and-release took hold.
The newer problems are harder. The U.S. Fish and Wildlife Service and SUNY ESF attribute the recent decline to the arrival of round goby, to viral hemorrhagic septicemia, and to continued loss of spawning habitat. Since the late 2010s, the Thousand Islands Biological Station, NYSDEC and the Fish and Wildlife Service have run an experimental program raising muskellunge from river spawners and stocking them back into the river and eastern Lake Ontario.
That context matters when you fish here. Every adult in this river is part of a population that people are actively trying to rebuild.
At the west end of the lake, NYSDEC lists the lower Niagara River among New York’s naturally reproducing muskellunge fisheries. It is fast, deep current water feeding into Lake Ontario at Youngstown, with a launch at Fort Niagara State Park in Porter. It is a niche fishery and a demanding place to run a boat. If you fish it, learn the river first.
Keep the fish in the water. Use a large cradle or rubber-coated net as a holding pen, unhook with long pliers or a cutter, and support it horizontally if you lift it for a photo. Keep air time to seconds. Hold it upright in the current until it leaves on its own.
The international boundary runs down the St. Lawrence and through the Thousand Islands. Stay on the U.S. side unless you hold an Ontario licence and know Ontario’s rules, and keep your chart plotter showing the line. Cape Vincent is the main U.S. launch at the head of the river.
New York’s muskellunge rules for the St. Lawrence, Lake Ontario and the Niagara River differ from its inland waters, and the Canadian half of the river is managed by Ontario. Seasons and size limits change. Read the current NYSDEC regulations, or Ontario’s if you cross the line, before you fish.
Where to put in
Dark marks are launches named in this guide. Generalized shoreline, not for navigation.
Kit
An 8-foot heavy musky stick that throws big rubber all day and still lets you finish a proper figure-eight boatside.
A round baitcaster built to throw 10-ounce rubber a thousand times a day and still have drag left for a 50-inch fish.
A big rubber bait with four independently moving tails that can be fished fast, slow, or as a slow-sinking glide.
The leader that stands between a Lake St. Clair muskie's teeth and your line, in the fluorocarbon that clear water demands.
The other standard in-line board — slightly larger, pulls heavier loads, and handles copper and lead core better than most.
A hoop big enough to take a fifty-inch St. Clair muskie without folding it, with a deep coated bag that becomes a holding pen boatside.
Questions
Same fish, other water
Size limits, bag limits, and open seasons for muskellunge on Lake Ontario are set by NYSDEC and change from year to year. Check the current rulebook before you keep a fish.
Sources
Last updated 2026-10-08
