Ontario Lake Depths
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Johnson Lake

Sudbury District, Ontario · MNRF bathymetric survey
6.1m Mapped depth
20 ft
5.4 ha 2 contours
Paddling Index69MixedMedium confidencesheltered geometry · wooded shoreline
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Depth scale

The lake

Survey readout

Johnson Lake is mapped to a depth of 6.1 m (20 ft) on the Ontario MNRF survey and covers about 5.4 ha (13 acres) in Sudbury District, Ontario. Depths come from the Ontario MNRF survey of 1967.

Measured from the Ontario MNRF bathymetry survey.

Deepest mapped contour
6.1 m (20 ft)
Survey year
1967
Surface area
5.4 ha (13 acres)
Shoreline
1.1 km (0.7 mi) · lobed
Fishing access
No MNRF fishing access point listed within 100 m (the list is incomplete)
Additional depth details2 contours
Contour depths
0–6.1 m (20 ft)
Deep-spot markers
6.1 m (20 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
46.73402, -81.58828
MNRF lake ID
17-4550-51756
Vertical exaggeration
3.0× below the waterline; land at true scale
Basemap
Ontario FRI
Model size
0.5 MB

Check the source: this lake’s record (17-4550-51756) 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: 1967. This model was built 2026-09-14. Depths between contours are interpolated, not measured.

Paddling

Paddling Index methodology v1.0 · calculated 2026-09-16
69 / 100MixedData confidence: Medium

Johnson Lake has a mostly natural, lightly developed setting, well sheltered geometry, nearby higher-volume roads.

Why this score?5 components

Included in the index

ComponentRatingPoints of weightMeasurement
Natural settingVery Good27.3 of 4374% natural land cover within 150 m of shore (73% forest, 1% wetland; 21% developed)
Geometric wind exposureExcellent35.7 of 36mean fetch 267 m · 100% of sampled water within 500 m of shelter · short fetch in most 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 isolationMixed6.5 of 21nearby higher-volume roads · 7 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
Moderate — narrow in places — wakes would carry across parts 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 — 73% forest and 1% wetland cover within 150 m of shore
Mapped wildlife habitat
Mapped — Ontario MNRF has mapped moose aquatic feeding areas 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 · 2013–2025

What anglers say they caught here, logged trip by trip in Ontario’s Fish ON-Line app — most recently in July 2025.

24Trips logged
9Species
317Fish reported

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

All species & trip details9 species
Yellow Perch17 of 24 trips · 241 caught
Splake5 of 24 trips · 19 caught
Smallmouth Bass5 of 24 trips · 13 caught
Brook Trout3 of 24 trips · 9 caught
Brown Trout3 of 24 trips · 5 caught
Northern Pike2 of 24 trips · 7 caught
Black Crappie1 trip · one angler’s report · 20 caught
Lake Trout1 trip · one angler’s report · 2 caught
Burbot1 trip · one angler’s report · 1 caught

How people fish it: ice 54% · shore 25% · boat 21%
Catch rate: about 3.0 fish an hour, all species together (24 trips, 104 hours logged)
Kept: 14% 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

Johnson Lake — common questions

How deep is Johnson Lake?

The deepest contour on the Ontario MNRF bathymetric survey of Johnson Lake is 6.1 m (20 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 Johnson Lake?

Johnson Lake covers about 5.4 ha (13 acres) in Sudbury District, Ontario.

Is there public access to Johnson Lake?

No fishing access point for Johnson 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.