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Map of Castle Lake with depth contours

Castle Lake

50.1269° N, 88.8722° W

Depth contours from the 1978 government survey. Not for navigation.

Download the depth map (SVG)

Castle Lake, Ontario. 50.1269° N, 88.8722° W

Maximum depth 36 m (1978 survey). Scale bar on the map.

Not for navigation. Depths are from government surveys and may be outdated.

borealbound.ca/lakes/on/castle-lake/, compiled October 9, 2026

  • Canadian Geographical Names Database, Natural Resources Canada. Contains information licensed under the Open Government Licence – Canada.
  • HydroLAKES v1.0, Messager et al. 2016 / WWF HydroSHEDS. Licensed under CC BY 4.0.
  • Census boundaries and population, 2021, Statistics Canada. Adapted from Statistics Canada. This does not constitute an endorsement by Statistics Canada.
  • Aquatic Resource Area survey points, Ontario Ministry of Natural Resources. Contains information licensed under the Open Government Licence – Ontario.
  • Fisheries Management Zones, Ontario Ministry of Natural Resources. Contains information licensed under the Open Government Licence – Ontario.
  • Bathymetry lines and survey index, Ontario Ministry of Natural Resources. Contains information licensed under the Open Government Licence – Ontario.
  • City page weather forecasts and alerts, Environment and Climate Change Canada. Contains data from Environment and Climate Change Canada (ECCC Data Servers End-use Licence).
  • Guide to Eating Ontario Fish: Advisory Database, Ontario Ministry of the Environment, Conservation and Parks. Contains information licensed under the Open Government Licence – Ontario.

Castle Lake is 36 m deep at its deepest point, deeper than 85% of the 2,688 surveyed lakes in Ontario. It covers 6.11 km² and lies 20 km southeast of Armstrong.

Government surveys have recorded 16 fish species here, including lake whitefish, lake trout and cisco.

Maximum depth
36 msurveyed 1978
deeper than 85% of the 2,688 surveyed lakes in Ontario
Area
6.11 km²
larger than 93% of the 18,731 lakes in Ontario
Shoreline
23.9 km
longer than 90% of the 18,731 lakes in Ontario
Fish species
16
more than 91% of the 2,454 surveyed lakes in Ontario
Elevation
300 m

Today on the water

-0.8 °C

ClearWind calmfeels like -4 °C

Observed at Gull Bay, as of 3:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 2 p.m., wind from the southeast: the southeast shore is sheltered, waves build toward the northwest shore.

Time4 a.m.7 a.m.10 a.m.1 p.m.4 p.m.7 p.m.10 p.m.1 a.m.
Wind km/hW 15W 10SW 10SE 10SE 15S 15S 20SE 30
Gusts km/h4050
Waves (est.) m0.10.10.10.1
Temp. °C4259121198
Precip. %2020202040404040

Tonight: Mainly cloudy. 30 percent chance of showers early this evening. Clearing near midnight. Wind north 20 km/h gusting to 40 becoming light this evening. Low plus 2.

Weather: Gull Bay (local forecast), as of 3:02 a.m. EDT

Sun and moon

Civil dawn
7:35 a.m.
Sunrise
8:08 a.m.
Sunset
7:16 p.m.
Civil dusk
7:48 p.m.
Moonrise
7:00 a.m.
Moonset
6:35 p.m.
Moon
Waning crescent, 1% lit

Data Source: Environment and Climate Change Canada. Local times.

How waves are estimated

Significant wave height from the forecast hourly wind and the open-water distance (fetch) upwind, using the SMB method (US Army Corps of Engineers Shore Protection Manual, 1984), rounded up to the next 0.1 m. It is not a measurement: gusts, leftover swell and shoals can make water rougher. Under 0.2 m: calm; 0.2–0.5 m: choppy; over 0.5 m: rough.

Depth

13% of Castle Lake is deeper than 20 m.

How to read it: the lake’s area is sorted from the shore to the deepest point. Where the curve is flat, large areas share one depth (flats and weed beds); where it drops, depth changes quickly (drop-offs).

The government depth survey from 1978 records a maximum depth of 36 m, drawn from 17 depth contours.

Not for navigation. Depths are from government surveys and may be outdated.

Fish

Sport fish by the share of the 31 government surveys (2013–2013) that recorded them.

  • Lake Whitefish26 of 31
  • Lake Trout22 of 31
  • Cisco14 of 31
  • Burbot13 of 31
  • Yellow Perch13 of 31
  • Northern Pike5 of 31
Forage fish and other species (10)

Forage fish

  • Mimic Shiner 5
  • Spottail Shiner 5
  • Blacknose Shiner 4
  • Johnny Darter 3
  • Northern Pearl Dace 3
  • Spoonhead Sculpin 3
  • Trout-Perch 3
  • Logperch 2
  • Ninespine Stickleback 2

Other

  • White Sucker 14

Numbers are the surveys that recorded each species.

Eating your catch

The provincial guide to eating fish (2026) sets limits for 6 species from Castle Lake. Maximum meals per month:

SpeciesLengthGeneral populationSensitive population*Contaminant
Lake Trout50-55 cm124Mercury
Lake Whitefish45-50 cm1616Precautionary
Northern Pike55-60 cm1612Precautionary
Yellow Perch25-30 cm168Mercury
Burbot (Ling)50-55 cm84Mercury
White Sucker40-45 cm1616Precautionary

* As defined in the guide, including children and people who are or may become pregnant. Limits are for the length the guide lists most often; they change with the size of the fish. Read the official guide

Fishing regulations: Fisheries Management Zone 6. Check seasons and limits before you fish.