Grand Portage Lake
Iron County, Wisconsin · WBIC 2314100
This lake has fishing rules that differ from the standard ones for its area. Check the official rules before you fish. Official regulations
Size
144 acres
Max depth
33 ft
DNR lake type
Complex, Cool, clear water color
Water clarity
10 ft
Clear, measured Sep 2026
A cool-water lake type: the DNR groups it with lakes that stay cooler through summer. This describes the lake type in general, not this lake in particular.
Outline
Numbered dots are boat landings; tap one for directions. The list below has the same numbers. Drawn from the DNR's 24K hydrography (surveyed 1981), so the shape is approximate and a landing can sit a little off the shore. Open the DNR lake map.
Water clarity
10 ft Secchi depthClear
Last measured Sep 21, 2026. 83 readings on record, 2002 to 2026.
Typical summer clarity (June to September): 10.2 ft, clear, from 58 readings (2012 to 2026).
Secchi depth is how far down a white disk stays visible. A bigger number means clearer water. Clear means a Secchi depth of 10 feet or more, moderate 5 to 10 feet, low under 5 feet.
Wisconsin DNR water monitoring (volunteer and staff), via the Water Quality Portal; station GRAND PORTAGE LAKE - DEEPEST SPOT. Checked Oct 23, 2026.
Water temperature
63.3°F surface, measured Sep 21, 2026
Measured near the surface (0.3 m down). A single reading, not a daily value.
A typical year Modeled estimate
- Ice goes outabout Apr 25 (Apr 17 to Apr 30)
- Surface reaches 48°Fabout May 5 (Apr 26 to May 9)
- Surface reaches 64°Fabout May 26 (May 19 to Jun 1)
- June surface69°F, usually 68 to 71°F
- July surface75°F, usually 74 to 76°F
- August surface71°F, usually 70 to 73°F
Forms a warm top layer around May 8, lasting about 142 days.
A computer model of this lake's typical weather and water, built from 15 years, 2005 to 2019. Ranges show the middle half of years. The model was not calibrated against measured temperatures for this lake. It is an estimate, not a measurement.
Measured: Wisconsin DNR via the Water Quality Portal (checked Oct 23, 2026). Modeled: U.S. Geological Survey lake temperature data release (doi:10.5066/P9CA6XP8).
Today at the lake
Forecast: National Weather Service (no endorsement implied). Sunrise, sunset and moon phase are calculated. The moon phase can be a day off.
Stocking history
- Walleyelast stocked 2010 (small fingerling); stocked in 1 year since 2010
Stocking shows what was added to the lake, not what is in it now.
Wisconsin DNR annual fish stocking summary. Checked Oct 23, 2026.
Boat landings
- 1Grand Portage Lake RampBoat ramp · Concrete surface · Township
Directions
Wisconsin DNR public boat access sites. Checked Oct 23, 2026.
Water level and flow
U.S. Geological Survey gauges at or beside this lake. Readings are provisional and fetched when you open the page.
More lakes in Iron County
- San Domingo Lake0.6 miles away
- Echo Lake0.8 miles away
- Martha Lake0.8 miles away
- Mercer Lake1.2 miles away
- Little Martha Lake1.5 miles away
- Rice Lake1.5 miles away
Where this comes from
- Size, depth and lake typeWisconsin DNR lake classifications, checked Oct 23, 2026
- OutlineWisconsin DNR 24K hydrography, checked Oct 23, 2026
- Stocking historyWisconsin DNR annual fish stocking summary, checked Oct 23, 2026
- Regulations linkWisconsin DNR fishing regulations (linked, not restated), checked Oct 23, 2026
- Boat landingsWisconsin DNR public boat access sites, checked Oct 23, 2026
- Water clarityWisconsin DNR water monitoring, via the Water Quality Portal, checked Oct 23, 2026
- Measured temperatureWisconsin DNR water monitoring, via the Water Quality Portal, checked Oct 23, 2026
- Typical-year temperatureU.S. Geological Survey lake temperature model (modeled estimate), checked Oct 23, 2026
- Water level and flowU.S. Geological Survey gauges (readings are live), checked Oct 23, 2026
- VHS statusWisconsin DNR VHS status by watershed, checked Oct 24, 2026
- Depth map linkWisconsin DNR lake maps list, checked Oct 24, 2026
See data sources for what each source covers, and about for how the numbers are matched to lakes.
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