Three Island Lake Fishing in Boise County, Idaho

• Overview

  Boise County, Idaho, is where Three Island Lake sits. It lies 8,596 feet above sea level. It covers about 11 acres, so this is small water you can walk round in under an hour. For supplies, Ketchum is 40 miles out. For a city, Boise is 62 miles off. Within a short drive: 0.6 miles out stands Rock Slide Lake, Low Pass Lake about 0.7 miles, 0.9 miles out stands Benedict Lake, Plummer Lake about 0.9 miles and 1 mile out stands Lake Ingeborg. It sits well inside its county, with no border complications.

• Where to Fish on Three Island Lake

  There is no published depth for this one, so start shallow and work out. On a natural lake the weed line and the shelf beyond it do the work. A soft bed grows weed late into autumn, which keeps fish shallow. Across Boise County, recorded fish include cutthroat trout, rainbow trout and california golden trout. At least one recorded species is protected in parts of its range; read the local rules before targeting anything. On Three Island Lake that means starting tight and working out.

• Seasonal Patterns

  The warmest month averages 52°F, the coldest about 16°F. Cold locks it up for a good stretch each year. The open season starts with the thaw, near enough late May. Expect the water usable from around late May until roughly early November. The weeks after the thaw and the ones before the freeze are the strongest. Anyone fishing Three Island Lake regularly works to that calendar.

• Tackle & Baits

  Whether the bank is open is not something our records settle. Formal access is not mapped, so the last stretch is likely on foot. Light line and small metal for the trout; a fly rod earns its place on calm evenings. Gates get locked out of season on water like this. Some water is controlled locally without a sign saying so. Rock Slide Lake, 0.6 miles away, makes the obvious fallback. Rules at Three Island Lake are worth checking on the day.