Ontario Lake Depths
NESW

Big Clear Lake

Frontenac County, Ontario · MNRF bathymetric survey
18m Mapped depth
59 ft
325 ha 10 contours
Paddling Index40ModestMedium confidence
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Depth scale

The lake

Survey readout

Big Clear Lake is mapped to a depth of 18 m (59 ft) on the Ontario MNRF survey and covers about 325 ha (802 acres) in Frontenac County, Ontario. Depths come from the Ontario MNRF survey of 1984.

Measured from the Ontario MNRF bathymetry survey.

Deepest mapped contour
18 m (59 ft)
Survey year
1984
Surface area
325 ha (802 acres)
Shoreline
16.3 km (10.1 mi) · irregular
Fishing access
No MNRF fishing access point listed within 100 m (the list is incomplete)
Additional depth details10 contours
Contour depths
0–18 m (59 ft)
Deep-spot markers
18 m (59 ft)
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Chart data

Provenance

Sources: Ontario MNRF / LIO Bathymetry, Ontario FRI Leaf-On Imagery, Ontario FRI LiDAR DTM, OpenStreetMap (ODbL), Contains information licensed under the Open Government Licence – Ontario.

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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 Ontario LiDAR (FRI DTM) elevation, with a Ontario FRI aerial basemap and OpenStreetMap shoreline. Colour shows surveyed depth; dark lines are the survey's own isobaths.

Coordinates
44.72658, -76.90577
MNRF lake ID
18-3490-49540
Vertical exaggeration
1.67×
Basemap
Ontario FRI
Model size
1.7 MB

Check the source: this lake’s record (18-3490-49540) 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: 1984. This model was built 2026-09-06. Depths between contours are interpolated, not measured.

Paddling

Paddling Index methodology v1.0 · calculated 2026-09-16
40 / 100ModestData confidence: Medium

Big Clear Lake has a partly natural setting, moderate open-water exposure, nearby higher-volume roads.

Why this score?5 components

Included in the index

ComponentRatingPoints of weightMeasurement
Natural settingGood19.6 of 4359% natural land cover within 150 m of shore (39% forest, 20% wetland; 40% developed)
Geometric wind exposureGood15.5 of 36mean fetch 1,576 m · 0% of sampled water within 500 m of shelter · moderate open-water fetch
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 isolationMixed5.2 of 21nearby higher-volume roads · 88 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
Moderate — 39% forest and 20% wetland cover within 150 m of shore
Mapped wildlife habitat
Mapped — Ontario MNRF has mapped deer wintering area within 1 km of this lake. These are habitat records from provincial surveys, not animal counts; areas with nothing mapped may still hold wildlife. · 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.

Angler catch reports

Fish ON-Line · 2015–2026

What anglers say they caught here, logged trip by trip in Ontario’s Fish ON-Line app — most recently in August 2026.

6Trips logged
6Species
175Fish reported

Pictures are sized relative to each other. Illustrations are AI-generated representative adults in everyday colours, not photographs (provenance).

Walleye4 of 6 trips · 4 caught
Largemouth Bass3 of 6 trips · 42 caught
Black Crappie3 of 6 trips · 6 caught
Pumpkinseed2 of 6 trips · 101 caught
Smallmouth Bass2 of 6 trips · 18 caught
Northern Pike2 of 6 trips · 4 caught

How people fish it: boat 83% · ice 17%
Catch rate: about 6.2 fish an hour, all species together (6 trips, 28 hours logged)
Kept: 4% of the fish reported; the rest were released

Trips are logged voluntarily by anglers in Ontario’s Fish ON-Line app. This is what people report catching, not a Ministry survey, and a species nobody has logged may still be here. Contains information licensed under the Open Government Licence – Ontario. Source: Ontario Ministry of Natural Resources, Fish ON-Line. A logged catch does not mean it is legal to catch or keep: check the Ontario Fishing Regulations Summary for this lake’s zone and exceptions.
Quick answers

Big Clear Lake — common questions

How deep is Big Clear Lake?

The deepest contour on the Ontario MNRF bathymetric survey of Big Clear Lake is 18 m (59 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 Big Clear Lake?

Big Clear Lake covers about 325 ha (802 acres) in Frontenac County, Ontario.

Is there public access to Big Clear Lake?

No fishing access point for Big Clear Lake appears in the Ontario MNRF fishing access point list (within 100 m of the shoreline). That is not the same as the lake being private -- the MNRF list is incomplete, and many municipal, marina and private launches are not in it.