Ontario Lake Depths
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Granite Lake

Thunder Bay District, Ontario · MNRF bathymetric survey
20m Mapped depth
66 ft
1,970 ha 10 contours
Paddling Index72GoodMedium confidenceaway from major roads · wooded shoreline
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Depth scale

The lake

Survey readout

Granite Lake is mapped to a depth of 20 m (66 ft) on the Ontario MNRF survey and covers about 1,970 ha (4,868 acres) in Thunder Bay District, Ontario.

Measured from the Ontario MNRF bathymetry survey.

Deepest mapped contour
20 m (66 ft)
Surface area
1,970 ha (4,868 acres)
Shoreline
141.2 km (87.7 mi) · irregular
Fishing access
No MNRF launch listed · check with Wabakimi Provincial Park
In
Wabakimi Provincial Park · Ontario Parks
Additional depth details10 contours
Contour depths
0–20 m (66 ft)
Deep-spot markers
20 m (66 ft)
Compare with another lake
Chart data

Provenance

Sources: Ontario MNRF / LIO Bathymetry, Ontario FRI Leaf-On Imagery, OpenStreetMap (ODbL), Contains information licensed under the Open Government Licence – Ontario, Copernicus DEM 30 m (© DLR/Airbus).

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Map details & sources5 sources

All layers registered to one bounding box; positions in WGS 84.

Survey-derived depth contours drape over Copernicus DEM (30 m) elevation, with a Ontario FRI aerial basemap and OpenStreetMap shoreline. Colour shows surveyed depth; dark lines are the survey's own isobaths.

Coordinates
50.47353, -89.76171
MNRF lake ID
16-3040-55939
Vertical exaggeration
2.21× below the waterline; land at true scale
Basemap
Ontario FRI
Model size
2.3 MB

Check the source: this lake’s record (16-3040-55939) in the Ontario MNRF bathymetry index, and the contour line layer the map is drawn from (Land Information Ontario open data, Open Government Licence – Ontario). Survey year: not recorded in the source. This model was built 2026-09-28. Depths between contours are interpolated, not measured.

Paddling

Paddling Index methodology v1.0 · calculated 2026-09-16
72 / 100GoodData confidence: Medium

Granite Lake has a heavily wooded and largely undeveloped setting, notable open-water exposure, little nearby major-road exposure.

Why this score?5 components

Included in the index

ComponentRatingPoints of weightMeasurement
Natural settingExcellent40.8 of 4394% natural land cover within 150 m of shore (84% forest, 10% wetland; 0% developed)
Geometric wind exposureMixed10.1 of 36mean fetch 2,318 m · 8% of sampled water within 500 m of shelter · long fetch in some directions
Motor & speed rulesNot modelled—Canada publishes vessel motor and speed restrictions as federal legal schedules, not map data, so they are not part of the Ontario index. Check local signage and Transport Canada rules before going out.
Public accessNot listed—No publicly listed MNRF fishing access point within 100 m of this shoreline. Municipal, private and informal launches are not all in this source, so this is not evidence that access is poor — the component is excluded and the remaining weights are renormalized.
Road isolationExcellent21.4 of 21relatively isolated from major roads · 0 Ontario Road Network segments within 1.2 km (traffic estimated from road class, not measured)

Additional paddling considerations

These describe the lake but are not part of the v1 Paddling Index and do not change the number above.

Wake sensitivity
Low — wide enough that wakes disperse over most of the lake
Observed motorized activity
Unknown — No lake-level measurement of boat traffic is available. Legal permission to operate motors is not evidence of use.
Wildlife habitat potential
High — 84% forest and 10% wetland cover within 150 m of shore
Mapped wildlife habitat
None mapped — Ontario MNRF has not mapped moose, deer or waterfowl habitat within 1 km of this lake. The province maps these areas where it has surveyed, so this is not evidence that wildlife is absent. · Ontario MNRF Wildlife Values Area. Contains information licensed under the Open Government Licence – Ontario.
How this index is calculated. The Paddling Index is a relative composite derived from lake geometry and public land-cover, access and road-network data. It is not a user review, a safety rating, or a prediction of an individual outing. Differences of a few points should not be treated as meaningful — an 84 and an 82 are broadly comparable. Components and weights for Ontario lakes: natural setting 35%, geometric wind exposure 29%, public access 18%, road isolation 18%. Motor and speed restrictions are not modelled for Ontario, and road traffic is estimated from road class, not measured. Where a component has no data the remaining weights are renormalized and the confidence rating is lowered; below Medium confidence no number is shown. Ontario scores are relative to other Ontario lakes and are not directly comparable with Paddling Index scores on our sister sites, which use different data sources and include a watercraft-rules component. Sources: Ontario MNRF bathymetry outline (0 m contour or survey index polygon), Ontario Land Cover v1.0, Ontario MNRF (Open Government Licence – Ontario) (2020) and Ontario Road Network (Open Government Licence – Ontario); traffic estimated by road class, not measured (2026-09). Conditions change quickly — check current weather and local conditions before going out.
Quick answers

Granite Lake — common questions

How deep is Granite Lake?

The deepest contour on the Ontario MNRF bathymetric survey of Granite Lake is 20 m (66 ft). That is the deepest depth the historical survey map records, which may differ from the deepest point of the lake itself.

How big is Granite Lake?

Granite Lake covers about 1,970 ha (4,868 acres) in Thunder Bay District, Ontario.

Is there public access to Granite Lake?

No fishing access point for Granite Lake appears in the Ontario MNRF fishing access point list (within 100 m of the shoreline), but Granite Lake lies inside Wabakimi Provincial Park (Ontario Parks), which runs its own facilities and is not covered by that data. Check with the park for launch details.