Big Rideau Lake – Portland

About this water

The deepest lake on the Rideau chain — a rare Eastern Ontario mix of native lake trout and a strong bass fishery.

One of the largest and deepest lakes on the Rideau system, with clear water and rocky shoals. FMZ 18.

FMZ 18 regulations — Eastern Ontario — Rideau & inland southeastern watersheds

Southeastern Ontario, built around the connecting lakes and rivers of the Rideau waterway, with the Canadian Shield at its heart and the St. Lawrence Lowlands to the east and west. It covers the Crowe, Mississippi, Napanee, Cataraqui, Rideau, Salmon, South Nation and Raisin River watersheds. It ends at Lake Ontario and the St. Lawrence River to the south (FMZ 20) and follows the Ottawa River (FMZ 12) to the north and east — the Ottawa and St. Lawrence Rivers themselves are not in FMZ 18.

• Walleye: 3rd Saturday in May – March 15; S-4/C-2.
• Muskie: 3rd Saturday in June – Dec 15; 137 cm min, S-1/C-0.
• Bass (large & small): 3rd Saturday in June – Nov 30; S-6/C-2.
• Lake trout (Big Rideau, Charleston): Jan 1 – Sept 30; S-2/C-1.

Zone check: FMZ 18 confirmed from this water's coordinates against the official Ontario zone boundaries (reviewed 2026-08-12).

Summary only — always confirm current seasons and limits on the Ontario MNRF FMZ 18 page before your trip.

Seasonal availability

Open-season windows for the species found at Big Rideau Lake – Portland, taken from the FMZ 18 regulation summary. Green months are within a published open season — they are not a prediction of how well fish will bite.

No FMZ 18 season line published in our summary for: Northern Pike. Check the official page before keeping these species.

Summary only, and seasons change annually. Confirm dates on the Ontario MNRF FMZ 18 page before your trip.

Fishing tips

• St. Lawrence smallmouth relate to current — drop-shot the drop-offs.
• Thousand Islands muskie respond to figure-8s at boatside — always finish the retrieve.
• Mid-lake shoals that top out at 8–15 ft are smallmouth magnets. Mark them once and you'll fish them for years.
• Access: Free or low-cost public lots at both access points.

Gear setup

Setup:

Medium spinning for bass; trolling for trout

Rod:

7' medium spinning rod

Reel:

Size 2500 spinning reel

Line:

10 lb braid with 8 lb fluorocarbon leader

Best bait:

Crayfish, Minnows, Smelt

Best lures:

Tube jigs, Drop-shot worms, Spoons, Jerkbaits