Cosgrave Lake, Ontario: Fishing Spots and Seasons

• Overview

  Cosgrave Lake sits in Thunder Bay District, out in Ontario. The bank is 436 metres above sea level. At some 5.95 sq km it is far too large to cover on foot in a day. The perimeter is close to 25 km, and wind can be flat in one arm and rough in the next. Few waters listed in Thunder Bay District are bigger. For supplies, Nipigon is 34 km out. Beyond it, Schreiber at 67 km and Greenstone at 78 km. Rules here are straightforward: one set of provincial rules.

• Where to Fish on Cosgrave Lake

  Without a survey to go on, judge depth from how the bank falls away. Read the surface for the wind lane, then fish the edge of it. This is a lake, so the margins and the first drop matter most. Public occurrence data for Thunder Bay District names cisco, blackfin cisco, rainbow smelt, bloater and shortjaw cisco. The county figures include rivers and lakes alike. At Cosgrave Lake light and wind decide more than tackle does.

• Seasonal Patterns

  Seasonal averages run from -18°C in January up to 16°C in July. The window is narrow, and fish feed hard while it lasts. Expect a solid lid for months and a thaw around early May. Break-up sits around early May on average, with the water closing again about mid November. The shoulder weeks of the open season are the productive ones. Plan around that when you fish Cosgrave Lake.

• Tackle & Baits

  Our records carry no access rule either way. Records list it as a natural water body rather than an impoundment. There is no mapped parking or launch close by, which usually means walking in. A light spinning outfit with a small box of lures and some bait covers most of what swims here. Rules for this water may differ from the county norm. Close seasons apply to some species and not others. Should this one be busy, Kilgour Lake is 2.8 km off. What applies at Cosgrave Lake may have changed since it was mapped.